BACKGROUND The pyruvate dehydrogenase E1 subunitβ(PDHB)gene which regulates energy metabolism is located in mitochondria.However,few studies have elucidated the role and mechanism of PDHB in different cancers.AIM To ...BACKGROUND The pyruvate dehydrogenase E1 subunitβ(PDHB)gene which regulates energy metabolism is located in mitochondria.However,few studies have elucidated the role and mechanism of PDHB in different cancers.AIM To comprehensive pan-cancer analysis of PDHB was performed based on bioinformatics approaches to explore its tumor diagnostic and prognostic value and tumor immune relevance in cancer.In vitro experiments were performed to examine the biological regulation of PDHB in liver cancer.METHODS Pan-cancer data related to PDHB were obtained from the Cancer Genome Atlas(TCGA)database.Analysis of the gene expression profiles of PDHB was based on TCGA and Genotype Tissue Expression Dataset databases.Cox regression analysis and Kaplan-Meier methods were used to assess the correlation between PDHB expression and survival prognosis in cancer patients.The correlation between PDHB and receiver operating characteristic diagnostic curve,clinicopathological staging,somatic mutation,tumor mutation burden(TMB),microsatellite instability(MSI),DNA methylation,and drug susceptibility in pan-cancer was also analyzed.Various algorithms were used to analyze the correlation between PDHB and immune cell infiltration and tumor chemotaxis environment,as well as the co-expression analysis of PDHB and immune checkpoint(ICP)genes.The expression and functional phenotype of PDHB in single tumor cells were studied by single-cell sequencing,and the functional enrichment analysis of PDHB-related genes was performed.The study also validated the level of mRNA or protein expression of PDHB in several cancers.Finally,in vitro experiments verified the regulatory effect of PDHB on the proliferation,migration,and invasion of liver cancer.RESULTS PDHB was significantly and differently expressed in most cancers.PDHB was significantly associated with prognosis in patients with a wide range of cancers,including kidney renal clear cell carcinoma,kidney renal papillary cell carcinoma,breast invasive carcinoma,and brain lower grade glioma.In some cancers,PDHB expression was clearly associated with gene mutations,clinicopathological stages,and expression of TMB,MSI,and ICP genes.The expression of PDHB was closely related to the infiltration of multiple immune cells in the immune microenvironment and the regulation of tumor chemotaxis environment.In addition,single-cell sequencing results showed that PDHB correlated with different biological phenotypes of multiple cancer single cells.This study further demonstrated that down-regulation of PDHB expression inhibited the proliferation,migration,and invasion functions of hepatoma cells.CONCLUSION As a member of pan-cancer,PDHB may be a novel cancer marker with potential value in diagnosing cancer,predicting prognosis,and in targeted therapy.展开更多
Objective:This study aimed to evaluate the effects of mitochondrial pyruvate carrier(MPC)blockade on the sensitivity of detection and radiotherapy of prostate cancer(PCa).Methods:We investigated glycolysis reprogrammi...Objective:This study aimed to evaluate the effects of mitochondrial pyruvate carrier(MPC)blockade on the sensitivity of detection and radiotherapy of prostate cancer(PCa).Methods:We investigated glycolysis reprogramming and MPC changes in patients with PCa by using metabolic profiling,RNASeq,and tissue microarrays.Transient blockade of pyruvate influx into mitochondria was observed in cellular studies to detect its different effects on prostate carcinoma cells and benign prostate cells.Xenograft mouse models were injected with an MPC inhibitor to evaluate the sensitivity of 18F-fluorodeoxyglucose positron emission tomography with computed tomography and radiotherapy of PCa.Furthermore,the molecular mechanism of this different effect of transient blockage towards benign prostate cells and prostate cancer cells was studied in vitro.Results:MPC was elevated in PCa tissue compared with benign prostate tissue,but decreased during cancer progression.The transient blockade increased PCa cell proliferation while decreasing benign prostate cell proliferation,thus increasing the sensitivity of PCa cells to 18F-PET/CT(SUVavg,P=0.016;SUVmax,P=0.03)and radiotherapy(P<0.01).This differential effect of MPC on PCa and benign prostate cells was dependent on regulation by a VDAC1-MPC-mitochondrial homeostasis-glycolysis pathway.Conclusions:Blockade of pyruvate influx into mitochondria increased glycolysis levels in PCa but not in non-carcinoma prostate tissue.This transient blockage sensitized PCa to both detection and radiotherapy,thus indicating that glycolytic potential is a novel mechanism underlying PCa progression.The change in the mitochondrial pyruvate influx caused by transient MPC blockade provides a critical target for PCa diagnosis and treatment.展开更多
In order to study the effects of ethyl pyruvate on cardiomyocyte apoptosis following ischemia/reperfusion (I/R) in vitro and the expression of Bcl-2 and Bax proteins, isolated rat hearts were perfused in a Langendor...In order to study the effects of ethyl pyruvate on cardiomyocyte apoptosis following ischemia/reperfusion (I/R) in vitro and the expression of Bcl-2 and Bax proteins, isolated rat hearts were perfused in a Langendorff model. Twenty-four rats were randomly divided into 3 groups (n=8 in each group): control group was perfused for 120 min. In the I/R group, after 30 min stabilization the injury was induced by 30 min global ischemia followed by 60 min reperfusion. Ethyl pyruvate (EP) group was set up with the same protocol as I/R group except that it was supplied with 2 mmol/L EP 15 rain before ischemia and throughout reperfusion. Myocardial malonaldehyde (MDA) content was measured. Myocardial apoptotic index (AI) was tested by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method. The expression of anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bax in cardiac myocytes was detected by immunohistochemistry. As compared with control group, the content of MDA, myocardial AI and the expression of Bcl-2, Bax proteins were increased significantly in I/R group, but the content of MDA, myocardial AI and the expression of Bax protein were decreased obviously and the expression of Bcl-2 protein was up-regulated in EP group (P〈0.05). These results demonstrate that EP could inhibit apoptosis of cardiac myocytes possibly via alleviating oxidative stress, up-regulating Bcl-2 and down-regulating Bax proteins.展开更多
BACKGROUND Study shows that signal transducer and activator of transcription 3(STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate de...BACKGROUND Study shows that signal transducer and activator of transcription 3(STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 in myeloma. STAT3 and pyruvate kinase M2(PKM2) can also be activated and enhance the Warburg effect in hepatocellular carcinoma. Precancerous lesions are critical to human and rodent hepatocarcinogenesis. However, the underlying molecular mechanism for the development of liver precancerous lesions remains unknown. We hypothesized that STAT3 promotes the Warburg effect possibly by upregulating p-PKM2 in liver precancerous lesions in rats.AIM To investigate the mechanism of the Warburg effect in liver precancerous lesions in rats.METHODS A model of liver precancerous lesions was established by a modified Solt-Farber method. The liver pathological changes were observed by HE staining and immunohistochemistry. The transformation of WB-F344 cells induced with Nmethyl-N'-nitro-N-nitrosoguanidine and hydrogen peroxide was evaluated by the soft agar assay and aneuploidy. The levels of glucose and lactate in the tissue and culture medium were detected with a spectrophotometer. The protein levels of glutathione S-transferase-π, proliferating cell nuclear antigen(PCNA), STAT3,and PKM2 were examined by Western blot and immunofluorescence.RESULTS We found that the Warburg effect was increased in liver precancerous lesions in rats. PKM2 and p-STAT3 were upregulated in activated oval cells in liverprecancerous lesions in rats. The Warburg effect, p-PKM2, and p-STAT3 expression were also increased in transformed WB-F344 cells. STAT3 activation promoted the clonal formation rate, aneuploidy, alpha-fetoprotein expression,PCNA expression, G1/S phase transition, the Warburg effect, PKM2 phosphorylation, and nuclear translocation in transformed WB-F344 cells.Moreover, the Warburg effect was inhibited by stattic, a specific inhibitor of STAT3, and further reduced in transformed WB-F344 cells after the intervention for PKM2.CONCLUSION The Warburg effect is initiated in liver precancerous lesions in rats. STAT3 activation promotes the Warburg effect by enhancing the phosphorylation of PKM2 in transformed WB-F344 cells.展开更多
BACKGROUND: The pathogenesis and progression of acute liver failure (ALF) are closely associated with intestinal endotoxemia because of the high permeability of the intestinal wall. Treatment with ethyl pyruvate (EP) ...BACKGROUND: The pathogenesis and progression of acute liver failure (ALF) are closely associated with intestinal endotoxemia because of the high permeability of the intestinal wall. Treatment with ethyl pyruvate (EP) has been shown to protect liver failure effectively. The current study aimed to explore the relationship between proinflammatory cytokines and intestinal permeability, and to investigate whether EP administration might prevent the release of multiple proinflammatory cytokines and decrease intestinal permeability and therefore, protect the liver from injury. METHODS: The ALF model was induced by D-galactosamine in rats. The rats were randomly divided into control (saline i.p.), model (D-galactosamine, 1.2 g/kg, i.p.), prevention [EP injection (40 mg/kg) 2 hours ahead of D-galactosamine] and treatment groups (EP injection 2 hours after D-galactosamine) Samples were obtained at 12 and 24 hours after ALF induction respectively. The histology of liver and intestinal tissue was accessed. Serum alanine aminotransferase, endotoxin, D(-) lactate, diamine oxidase (DAO), tumor necrosis factor-alpha (TNF-α), interferon-γ (IFN-γ) and high mobility group box-1 (HMGB1) were evaluated. The survival of rats was also recorded. RESULTS: The rats in model group showed severe damage to liver tissue and intestinal mucosa 12 and 24 hours after ALF induction. EP significantly improved liver or intestinal injury In addition, serum endotoxin, D(-)-lactate, DAO, TNF-α IFN-γ and HMGB1 levels were significantly increased in the model group compared with the control group. There was a positive correlation between intestinal permeability andproinflammatory cytokines. EP significantly reduced serum endotoxin, D(-)-lactate, DAO, TNF-α, IFN-γ and HMGB1 levels. The median survival time was significantly prolonged in both prevention and treatment groups (126 and 120 hours compared with 54 hours in the model group). CONCLUSIONS: EP has protective and therapeutic effects on intestinal mucosa. EP decreases intestinal permeability, and inhibits the release of multiple proinflammatory cytokines in rats with ALF.展开更多
Type A lactic acidosis resulted from hypoxic mitochondrial dysfunction is an independent predictor of mortality for critically ill patients. However, current therapeutic agents are still in shortage and can even be ha...Type A lactic acidosis resulted from hypoxic mitochondrial dysfunction is an independent predictor of mortality for critically ill patients. However, current therapeutic agents are still in shortage and can even be harmful. This paper reviewed data regarding lactic acidosis treatment and recommended that pyruvate might be a potential alkalizer to correct type A lactic acidosis in future clinical practice. Pyruvate is a key energy metabolic substrate and a pyruvate dehydrogenase(PDH) activator with several unique beneficial biological properties, including anti-oxidant and antiinflammatory effects and the ability to activate the hypoxia-inducible factor-1(HIF-1α)-erythropoietin(EPO) signal pathway. Pyruvate preserves glucose metabolism and cellular energetics better than bicarbonate, lactate, acetate and malate in the efficient correction of hypoxic lactic acidosis and shows few side effects. Therefore, application of pyruvate may be promising and safe as a novel therapeutic strategy in hypoxic lactic acidosis correction accompanied with multi-organ protection in critical care patients.展开更多
AIM:To investigate the expression and prognostic role of pyruvate dehydrogenase(PDH) in gastric cancer(GC).METHODS:This study included 265 patients(194 male,71 female,mean age 59 years(range,29-81 years) with GC who u...AIM:To investigate the expression and prognostic role of pyruvate dehydrogenase(PDH) in gastric cancer(GC).METHODS:This study included 265 patients(194 male,71 female,mean age 59 years(range,29-81 years) with GC who underwent curative surgery at the First Affiliated Hospital of China Medical University from January 2006 to May 2007.All patients were followed up for more than 5 years.Patient-derived paraffin embedded GC specimens were collected for tissue microarrays(TMAs).We examined PDH expression by immunohistochemistry in TMAs containing tumor tissue and matched nonneoplastic mucosa.Immunoreactivity was evaluated independently by two researchers.Overall survival(OS) rates were determined using the Kaplan-Meier estimator.Correlations with other clinicopathologic factors were evaluated by two-tailed χ2 tests or a two-tailed t-test.The Cox proportional-hazard model was used in univariate analysis and multivariate analysis to identify factors significantly correlated with prognosis.RESULTS:Immunohistochemistry showed that 35.47% of total cancer tissue specimens had cytoplasmic PDH staining.PDH expression was much higher in normal mucosa specimens(75.09%;P = 0.001).PDH expression was correlated with Lauren grade(70.77% in intestinal type vs 40.0% in diffuse type;P = 0.001),lymph node metastasis(65.43% with no metastasis vs 51.09% with metastasis;P = 0.033),lymphatic invasion(61.62% with no invasion vs 38.81% with invasion;P = 0.002),histologic subtypes(70.77% in intestinal type vs 40.0% in diffuse type;P = 0.001) and tumor-node-metastasis(TNM) stage(39% in poorly differentiated vs 65.91% in well differentiated and 67.11% in moderately differentiated;P = 0.001) in GC.PDH expression in cancer tissue was significantly associated with higher OS(P < 0.001).The multivariate analysis adjusted for age,Lauren classification,TNM stage,lymph node metastasis,histological type,tumor size,depth of invasion and lymphatic invasion showed that the PDH expression in GC was an independent prognostic factor for higher OS(HR = 0.608,95%CI:0.504-0.734,P < 0.001).CONCLUSION:Our study indicated that PDH expression is an independent prognostic factor in GC patients and that positive expression of PDH may be predictive of favorable outcomes.展开更多
To assess the effects ofcreatine pyruvate (Cr-Pyr) on lipid and protein metabolism in broiler chickens, a total of 400 1-day-old male birds (Aconred) were randomly allocated to four groups, with each group replica...To assess the effects ofcreatine pyruvate (Cr-Pyr) on lipid and protein metabolism in broiler chickens, a total of 400 1-day-old male birds (Aconred) were randomly allocated to four groups, with each group replicating four times and each replicate involving 25 birds. The broilers were provided with a commercial diet supplemented with Cr-Pyr at 0, 1, 5, or 10% of the diet, respectively, for a period of 3 wk ad libitum (from 22 to 42 d). In the present study, body weight (BW) and average daily gain (ADG) of broilers decreased in 10% Cr-Pyr group (P〈0.01), whereas the relative leg and pectoral muscle weights were significantly higher than they were in the control group (P〈0.05). 5 or 10% Cr-Pyr of diets decreased the abdominal fat rate (AFR, abdominal fat/live weight) of the broilers. The serum or hepatic triglyceride (TG) concentrations were significantly lower in the 5 and 10% groups (P〈0.01). In contrast, Cr-Pyr caused a marked increase in the serum nonesterified fatty acid (NEFA), high-density lipoprotein cholesterol (HDL-C) and creatine kinase (CK) concentrations (P〈0.01). Supplementation with Cr-Pyr (5 and 10%) in the diet also increased glucagons (GLU), insulin (INS) or leptin (LEP) contents (P〈0.01). The expression of hepatic peroxisomal proliferators-activated receptor α (PPAR-α) and carnitine palmitoyl transferase-I (CPT-I), muscle insulin-like growth factor I (IGF-I) were significantly elevated and myostatin mRNA level was reduced in the 5 and 10% groups (P〈0.05). It was found that supplementation with 5% Cr-Pyr improves both lipid and protein metabolism by regulating various metabolic parameters of broilers, while not adversely affects growth performance in broiler chickens.展开更多
Gastrointestinal(GI) cancer is one of the most common causes of cancer-related deaths worldwide.Tumor markers are valuable in detecting post-surgical recurrence or in monitoring response to chemotherapy.Pyruvate kinas...Gastrointestinal(GI) cancer is one of the most common causes of cancer-related deaths worldwide.Tumor markers are valuable in detecting post-surgical recurrence or in monitoring response to chemotherapy.Pyruvate kinase isoform M2(PKM2),a glycolytic enzyme catalyzing conversion of phosphoenolpyruvate(PEP) to pyruvate,confers a growth advantage to the tumor cells and enables them to adapt to the tumor microenvironment.In this review,we have summarized current research on the expression and regulation of PKM2 in tumor cells,and its potential role in GI carcinogenesis and progression.Furthermore,we have also discussed the potential of PKM2 as a diagnostic and screening marker,and a therapeutic target in GI cancer.展开更多
The objective of this study was to characterize the oxygen dependent regulation of pyruvate oxidase (SpxB) gene expression and protein production in Streptococcus sanguinis (S. sanguinis). SpxB is responsible for ...The objective of this study was to characterize the oxygen dependent regulation of pyruvate oxidase (SpxB) gene expression and protein production in Streptococcus sanguinis (S. sanguinis). SpxB is responsible for the generation of growth-inhibiting amounts of hydrogen peroxide (H202) able to antagonize cariogenic Strepto- coccus mutans (S. mutans). Furthermore, the ecological consequence of H202 production was investigated in its self-inhibiting ability towards the producing strain. Expression of spxB was determined with quantitative Real-Time RT-PCR and a fluorescent expression reporter strain. Protein abundance was investigated with FLAG epitope engineered in frame on the C-terminal end of SpxB. Self inhibition was tested with an antagonism plate assay. The expression and protein abundance decreased in cells grown under anaerobic conditions. S. sanguinis was resistant against its own produced H202, while cariogenic S. mutans was inhibited in its growth. The results suggest that S. sanguinis produces H202 as antimicrobial substance to inhibit susceptible niche competing species like S. mutans during initial biofilm formation, when oxygen availability allows for spxB expression and Spx production.展开更多
Background: Salmonella enter/ca serovar Typhimurium is a major foodborne pathogen worldwide. S. Typhimurium encodes type III secretion systems via Salmonella pathogenicity islands (SPI), producing the major effecto...Background: Salmonella enter/ca serovar Typhimurium is a major foodborne pathogen worldwide. S. Typhimurium encodes type III secretion systems via Salmonella pathogenicity islands (SPI), producing the major effector proteins of virulence. Previously, we identified two genes of Salmonella pyruvate metabolism that were up-regulated during chicken cell infection: pyruvate formate lyase I (pf/B) and b/functional acetaldehyde-CoA/alcohol dehydrogenase (adhE). We were therefore interested in examining the role these genes may play in the transmission of Salmonella to humans. Methods: Mutant strains of Salmonella with single gene deletions for pflB and adhE were created. Invasion and growth in human HCT-8 intestinal epithelial cells and THP-1 macrophages was examined. Quantitative PCR was performed on 19 SPI-1 genes. Results: In HCT-8 cells, both mutant strains had significantly higher intracellular counts than the wild-type from 4 to 48 h post-infection. Various SPI-1 genes in the mutants were up-regulated over the wild-type as early as 1 h and lasting until 24 h post-infection. In THP-1 cells, no significant difference in internal Salmonella counts was observed; however, SPI-1 genes were largely down-regulated in the mutants during the time-course of infection. We also found five SPI-1 genes - hilA, hiIC hill), sicP and rtsA - which were up-regulated in at least one of the mutant strains in log-phase broth cultures alone. We have therefore identified a set of SPI-1 virulence genes whose regulation is effected by the central metabolism of Salmonella.展开更多
Modification of transition metal cations to polymer-stabilized Pt colloidal clusters modified with cinchonidine was studied in enantioselective hydrogenation of methyl pyruvate.Compared to the enantiomeric excess(e.e....Modification of transition metal cations to polymer-stabilized Pt colloidal clusters modified with cinchonidine was studied in enantioselective hydrogenation of methyl pyruvate.Compared to the enantiomeric excess(e.e.)value(71.4%) obtained without the presence of metal cations,obvious e.e.enhancement(up to 82.5%)was resulted from the addition of Zn^(2+) but with a certain decrease in activity.The reaction parameters in the presence of Zn^(2+) were also studied.It was found that the Pt colloidal catalysts in the presence of metal cations performed very differently from that in the absence of metal cations.展开更多
Pyruvate, orthophosphate dikinase (PPDK) and phosphoenolpyruvate synthetase (PEPS) catalyze the conversion of pyruvate to phosphoenolpyruvate (PEP). Both are regulated by a phosphorylation-dephosphorylation mechanism ...Pyruvate, orthophosphate dikinase (PPDK) and phosphoenolpyruvate synthetase (PEPS) catalyze the conversion of pyruvate to phosphoenolpyruvate (PEP). Both are regulated by a phosphorylation-dephosphorylation mechanism involving a bifunctional serine/ threonine kinase and a pyrophosphorylase (PPDK regulatory protein, PDRP, and PEPS regulatory protein, PSRP, respectively). In plants the regulatory mechanism involves phosphorylation of a threonine residue that is separated by a single amino acid from the histidine residue that forms a phosphorylated intermediate during catalysis. Using antibodies, we demonstrated that the regulation of both Listeria monocytogenes PPDK and Escherichia coli PEP synthetase involves the phosphorylation of a threonine residue located close to the catalytic histidine residue. The amino acid located between the regulatory threonine and the catalytic histidine is highly conserved being serine in PPDK and cysteine in PEPS. Using site-directed mutagenesis we have shown that both PPDK and PEPS in which the serine and cysteine residues, respectively, were substituted with an alanine the enzymes could be regulated indicating that the serine and cysteine residues, respectively, are not essential for regulation. We also demonstrated that altering the intermediate amino acid did not alter the specificity of the regulatory proteins for their protein substrates.展开更多
The polysaccharide was isolated from Hypnea pannosa which was grown in Okinawa, Japan. The yield of the polysaccharide was 17.2%, and the total carbohydrates, pyruvic acid, sulfuric acid and ash contents were 55.2%, 3...The polysaccharide was isolated from Hypnea pannosa which was grown in Okinawa, Japan. The yield of the polysaccharide was 17.2%, and the total carbohydrates, pyruvic acid, sulfuric acid and ash contents were 55.2%, 3.8%, 35.2% and 24.3%, respectively. 3,6-Anhydro-α-D-galactose, β-D-galactose, α-D-galactose and D-glucose were identified by liquid and thin-layer chromatography. Fourier transform infrared (FTIR) spectra of the polysaccharide resembled that of ι-carrageenan. From the <sup>1</sup>H- and <sup>13</sup>C-NMR spectra, 1,3-linked β-D-galactose, 1,4-linked anhydro-α-D-galactose, 1,4-linked α-D-galactose, 1,4-linked β-D-glucose and pyruvic acid (carboxyl acetal, methyl proton and methyl carbon) were assigned. Methylation analysis revealed terminal D-galactose 0.1 mol), 1,4-linked D-glucose (1.0 mol) and 1,2,3,4,6-linked D-galactose (3.7 mol) for native polysaccharide, and terminal D-galactose, 1,4-linked D-galactose (1.9 mol), 1,4-linked D-glucose (1.0 mol), 1,3- linked D-galactose (1.7 mol), and 1,3,4,6-linked D-galactose (0.3 mol) which substituted with pyruvate group at 4 and 6 positions for desulfated polysaccharide. The polysaccharide was the novel pyruvated glucogalactan sulfate, the structure of which was proposed.展开更多
A novel method of preparing pyruvate from DL-lactate catalyzed by enzymes from a bacterial strain of Pseudomonas sp. SM-6 was proposed. Catalytic processes of cell-free extract enzymes and immobilized enzymes were ev...A novel method of preparing pyruvate from DL-lactate catalyzed by enzymes from a bacterial strain of Pseudomonas sp. SM-6 was proposed. Catalytic processes of cell-free extract enzymes and immobilized enzymes were evaluated. The kinetic data were studied, too.展开更多
Pyruvate was produced from DL-lactate by a kind of green-chemical biocatalyst cell-free extract from bacterial strain Pseudomonas sp. SM-6. Catalase in cell-free extract, which could stabilize the pyruvate formed by...Pyruvate was produced from DL-lactate by a kind of green-chemical biocatalyst cell-free extract from bacterial strain Pseudomonas sp. SM-6. Catalase in cell-free extract, which could stabilize the pyruvate formed by lactate oxidase, played an important role in pyruvate preparation. The effect of catalase in conversion process was evaluated.展开更多
Pyruvate, a final metabolite of glycogen, is widely distributed over many kinds of tissue fluids of human bodys. The determination for its contents is of clinical importance in gynaecology. Titrimetry, colorimetry and...Pyruvate, a final metabolite of glycogen, is widely distributed over many kinds of tissue fluids of human bodys. The determination for its contents is of clinical importance in gynaecology. Titrimetry, colorimetry and chromatography are common used methods. In recent years, enzymatic mthod has proved to be one of the most important determination techniques for its simplicity and fastness. However, in some cases, the use of purified enzymes as biocatalysts yields systems with a short useful lifetime owing, to enzyme instability A tiss展开更多
The kinetics of oxidation of pyruvate by diperiodatoargentate( III) ion (DPA) has been studied spec-trophotometrically in alkaline medium. It was found that the reaction order with respect to both DPA and pyruvate is ...The kinetics of oxidation of pyruvate by diperiodatoargentate( III) ion (DPA) has been studied spec-trophotometrically in alkaline medium. It was found that the reaction order with respect to both DPA and pyruvate is unity and the rate equation can be expressed asThe rate increases with the increase in [OH ] and decreases with the increase in [periodate]. There is a positive ionic strength effect in this reaction system. A mechanism has been proposed to explain the experimental results. The observed activation parameters are presented.展开更多
BACKGROUND The understanding regarding genetic variation,pathophysiology,and complications associated with pyruvate kinase deficiency(PKD)in red blood cells has been explained largely,and supportive treatment is curre...BACKGROUND The understanding regarding genetic variation,pathophysiology,and complications associated with pyruvate kinase deficiency(PKD)in red blood cells has been explained largely,and supportive treatment is currently the main management strategy.Etiotropic managements,including transplantation and genome editing,supplying for substitute dugs of the pyruvate kinase,are all under research.CASE SUMMARY We herein report a 3-year-old boy with severe transfusion-dependent PKD cured by unrelated identical peripheral blood stem cell transplantation(PBSCT).Hemoglobin was corrected to a normal level by gene correction after PBSCT,with no complication related to the transplantation.CONCLUSION Hematopoietic stem cell transplantation could be a substitute for transfusiondependent PKD.展开更多
The purpose of this study is to investigate the perioperative changes of erythrocyte kinase (PK) activity. Thirty patients undergoing upper abdominal surgery were dirided into epidural blockade(EB) group or intra veno...The purpose of this study is to investigate the perioperative changes of erythrocyte kinase (PK) activity. Thirty patients undergoing upper abdominal surgery were dirided into epidural blockade(EB) group or intra venous procaine balanced anesthesia(IPBA) group. The blood level of glucose increased significantly at 60 min after the beginning of operations in both groups. Blood glucose levels on the first postoperative day were significantly higher than the baselines in both groups [(8. 29±1. 5)vs (4. 8±0.18) mmol/L (P< 0.01) in EB, (6.36±0.33) vs (4. 55±0.18 ) mmol/L (P<0. 01 ) in IPBA]. The concentrations of 2, 3-DPG in RBC were not significantly changed in both groups. The PK activity in RBC decreased signficantly at 60 min after the end of operation in both groups. The PK activity levels on the first postoperative day were significantly lower than the baselines in both groups [(7. 59±1. 01) vs (11. 62±1. 06) IU/gHb (P<0. 05) in EB; (7. 75±0. 94) vs (11. 84 ±1.12) IU/gHb (P<0. 05 ) in IPBA]. The results suggest that the PK activity is decreased and the concentration of 2, 3-DPG remians unchanged under the hyperglycemic response to surgical stress, which may be related to an inhibition of glycolysis in RBC.展开更多
基金Supported by The 2021 Central-Guided Local Science and Technology Development FundLanzhou COVID-19 Prevention and Control Technology Research Project,No.2020-XG-1Gansu Province Outstanding Graduate Student"Innovation Star"Project,No.2022CXZX-748,No.2022CXZX-746.
文摘BACKGROUND The pyruvate dehydrogenase E1 subunitβ(PDHB)gene which regulates energy metabolism is located in mitochondria.However,few studies have elucidated the role and mechanism of PDHB in different cancers.AIM To comprehensive pan-cancer analysis of PDHB was performed based on bioinformatics approaches to explore its tumor diagnostic and prognostic value and tumor immune relevance in cancer.In vitro experiments were performed to examine the biological regulation of PDHB in liver cancer.METHODS Pan-cancer data related to PDHB were obtained from the Cancer Genome Atlas(TCGA)database.Analysis of the gene expression profiles of PDHB was based on TCGA and Genotype Tissue Expression Dataset databases.Cox regression analysis and Kaplan-Meier methods were used to assess the correlation between PDHB expression and survival prognosis in cancer patients.The correlation between PDHB and receiver operating characteristic diagnostic curve,clinicopathological staging,somatic mutation,tumor mutation burden(TMB),microsatellite instability(MSI),DNA methylation,and drug susceptibility in pan-cancer was also analyzed.Various algorithms were used to analyze the correlation between PDHB and immune cell infiltration and tumor chemotaxis environment,as well as the co-expression analysis of PDHB and immune checkpoint(ICP)genes.The expression and functional phenotype of PDHB in single tumor cells were studied by single-cell sequencing,and the functional enrichment analysis of PDHB-related genes was performed.The study also validated the level of mRNA or protein expression of PDHB in several cancers.Finally,in vitro experiments verified the regulatory effect of PDHB on the proliferation,migration,and invasion of liver cancer.RESULTS PDHB was significantly and differently expressed in most cancers.PDHB was significantly associated with prognosis in patients with a wide range of cancers,including kidney renal clear cell carcinoma,kidney renal papillary cell carcinoma,breast invasive carcinoma,and brain lower grade glioma.In some cancers,PDHB expression was clearly associated with gene mutations,clinicopathological stages,and expression of TMB,MSI,and ICP genes.The expression of PDHB was closely related to the infiltration of multiple immune cells in the immune microenvironment and the regulation of tumor chemotaxis environment.In addition,single-cell sequencing results showed that PDHB correlated with different biological phenotypes of multiple cancer single cells.This study further demonstrated that down-regulation of PDHB expression inhibited the proliferation,migration,and invasion functions of hepatoma cells.CONCLUSION As a member of pan-cancer,PDHB may be a novel cancer marker with potential value in diagnosing cancer,predicting prognosis,and in targeted therapy.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant No.81902616 to F.W.)Science and Technology Support Project in the field of biomedicine of Shanghai Science and Technology Action Plan(Grant No.19441909200,F.W.)+6 种基金Clinical Research Project of Shanghai Municipal Commission of Health and Family Planning(Grant No.20184Y0130,F.W.)Precision Medicine Program of Second Military Medical University(Grant No.2017JZ35,F.W.)Youth Startup Program of the Second Military Medical University(Grant No.2016QN12,F.W.)Jiangsu Provincial Medical Youth Talent(Grant No.QNRC2016739,X.W.)Shanghai Sailing Program(Grant No.21YF1423300,H.X.)Natural Science Foundation of Shanghai(Grant No.21ZR1437800,H.X.)Cross-disciplinary Research Fund of Shanghai Ninth People’s Hospital,Shanghai Jiaotong University School of Medicine(Grant No.YG2021QN75,H.X.).
文摘Objective:This study aimed to evaluate the effects of mitochondrial pyruvate carrier(MPC)blockade on the sensitivity of detection and radiotherapy of prostate cancer(PCa).Methods:We investigated glycolysis reprogramming and MPC changes in patients with PCa by using metabolic profiling,RNASeq,and tissue microarrays.Transient blockade of pyruvate influx into mitochondria was observed in cellular studies to detect its different effects on prostate carcinoma cells and benign prostate cells.Xenograft mouse models were injected with an MPC inhibitor to evaluate the sensitivity of 18F-fluorodeoxyglucose positron emission tomography with computed tomography and radiotherapy of PCa.Furthermore,the molecular mechanism of this different effect of transient blockage towards benign prostate cells and prostate cancer cells was studied in vitro.Results:MPC was elevated in PCa tissue compared with benign prostate tissue,but decreased during cancer progression.The transient blockade increased PCa cell proliferation while decreasing benign prostate cell proliferation,thus increasing the sensitivity of PCa cells to 18F-PET/CT(SUVavg,P=0.016;SUVmax,P=0.03)and radiotherapy(P<0.01).This differential effect of MPC on PCa and benign prostate cells was dependent on regulation by a VDAC1-MPC-mitochondrial homeostasis-glycolysis pathway.Conclusions:Blockade of pyruvate influx into mitochondria increased glycolysis levels in PCa but not in non-carcinoma prostate tissue.This transient blockage sensitized PCa to both detection and radiotherapy,thus indicating that glycolytic potential is a novel mechanism underlying PCa progression.The change in the mitochondrial pyruvate influx caused by transient MPC blockade provides a critical target for PCa diagnosis and treatment.
文摘In order to study the effects of ethyl pyruvate on cardiomyocyte apoptosis following ischemia/reperfusion (I/R) in vitro and the expression of Bcl-2 and Bax proteins, isolated rat hearts were perfused in a Langendorff model. Twenty-four rats were randomly divided into 3 groups (n=8 in each group): control group was perfused for 120 min. In the I/R group, after 30 min stabilization the injury was induced by 30 min global ischemia followed by 60 min reperfusion. Ethyl pyruvate (EP) group was set up with the same protocol as I/R group except that it was supplied with 2 mmol/L EP 15 rain before ischemia and throughout reperfusion. Myocardial malonaldehyde (MDA) content was measured. Myocardial apoptotic index (AI) was tested by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method. The expression of anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bax in cardiac myocytes was detected by immunohistochemistry. As compared with control group, the content of MDA, myocardial AI and the expression of Bcl-2, Bax proteins were increased significantly in I/R group, but the content of MDA, myocardial AI and the expression of Bax protein were decreased obviously and the expression of Bcl-2 protein was up-regulated in EP group (P〈0.05). These results demonstrate that EP could inhibit apoptosis of cardiac myocytes possibly via alleviating oxidative stress, up-regulating Bcl-2 and down-regulating Bax proteins.
基金Supported by the National Natural Science Foundation of China,No.81070319the Beijing Natural Science Foundation of China,No.7102013the Beijing Municipal Education Commission Research Program,China,No.KM201610025004
文摘BACKGROUND Study shows that signal transducer and activator of transcription 3(STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 in myeloma. STAT3 and pyruvate kinase M2(PKM2) can also be activated and enhance the Warburg effect in hepatocellular carcinoma. Precancerous lesions are critical to human and rodent hepatocarcinogenesis. However, the underlying molecular mechanism for the development of liver precancerous lesions remains unknown. We hypothesized that STAT3 promotes the Warburg effect possibly by upregulating p-PKM2 in liver precancerous lesions in rats.AIM To investigate the mechanism of the Warburg effect in liver precancerous lesions in rats.METHODS A model of liver precancerous lesions was established by a modified Solt-Farber method. The liver pathological changes were observed by HE staining and immunohistochemistry. The transformation of WB-F344 cells induced with Nmethyl-N'-nitro-N-nitrosoguanidine and hydrogen peroxide was evaluated by the soft agar assay and aneuploidy. The levels of glucose and lactate in the tissue and culture medium were detected with a spectrophotometer. The protein levels of glutathione S-transferase-π, proliferating cell nuclear antigen(PCNA), STAT3,and PKM2 were examined by Western blot and immunofluorescence.RESULTS We found that the Warburg effect was increased in liver precancerous lesions in rats. PKM2 and p-STAT3 were upregulated in activated oval cells in liverprecancerous lesions in rats. The Warburg effect, p-PKM2, and p-STAT3 expression were also increased in transformed WB-F344 cells. STAT3 activation promoted the clonal formation rate, aneuploidy, alpha-fetoprotein expression,PCNA expression, G1/S phase transition, the Warburg effect, PKM2 phosphorylation, and nuclear translocation in transformed WB-F344 cells.Moreover, the Warburg effect was inhibited by stattic, a specific inhibitor of STAT3, and further reduced in transformed WB-F344 cells after the intervention for PKM2.CONCLUSION The Warburg effect is initiated in liver precancerous lesions in rats. STAT3 activation promotes the Warburg effect by enhancing the phosphorylation of PKM2 in transformed WB-F344 cells.
基金supported by a grant from the National Natural Science Foundation of China (81071342)
文摘BACKGROUND: The pathogenesis and progression of acute liver failure (ALF) are closely associated with intestinal endotoxemia because of the high permeability of the intestinal wall. Treatment with ethyl pyruvate (EP) has been shown to protect liver failure effectively. The current study aimed to explore the relationship between proinflammatory cytokines and intestinal permeability, and to investigate whether EP administration might prevent the release of multiple proinflammatory cytokines and decrease intestinal permeability and therefore, protect the liver from injury. METHODS: The ALF model was induced by D-galactosamine in rats. The rats were randomly divided into control (saline i.p.), model (D-galactosamine, 1.2 g/kg, i.p.), prevention [EP injection (40 mg/kg) 2 hours ahead of D-galactosamine] and treatment groups (EP injection 2 hours after D-galactosamine) Samples were obtained at 12 and 24 hours after ALF induction respectively. The histology of liver and intestinal tissue was accessed. Serum alanine aminotransferase, endotoxin, D(-) lactate, diamine oxidase (DAO), tumor necrosis factor-alpha (TNF-α), interferon-γ (IFN-γ) and high mobility group box-1 (HMGB1) were evaluated. The survival of rats was also recorded. RESULTS: The rats in model group showed severe damage to liver tissue and intestinal mucosa 12 and 24 hours after ALF induction. EP significantly improved liver or intestinal injury In addition, serum endotoxin, D(-)-lactate, DAO, TNF-α IFN-γ and HMGB1 levels were significantly increased in the model group compared with the control group. There was a positive correlation between intestinal permeability andproinflammatory cytokines. EP significantly reduced serum endotoxin, D(-)-lactate, DAO, TNF-α, IFN-γ and HMGB1 levels. The median survival time was significantly prolonged in both prevention and treatment groups (126 and 120 hours compared with 54 hours in the model group). CONCLUSIONS: EP has protective and therapeutic effects on intestinal mucosa. EP decreases intestinal permeability, and inhibits the release of multiple proinflammatory cytokines in rats with ALF.
基金supported by the National Natural Science Foundation of China(No.81700181,No.81600148)
文摘Type A lactic acidosis resulted from hypoxic mitochondrial dysfunction is an independent predictor of mortality for critically ill patients. However, current therapeutic agents are still in shortage and can even be harmful. This paper reviewed data regarding lactic acidosis treatment and recommended that pyruvate might be a potential alkalizer to correct type A lactic acidosis in future clinical practice. Pyruvate is a key energy metabolic substrate and a pyruvate dehydrogenase(PDH) activator with several unique beneficial biological properties, including anti-oxidant and antiinflammatory effects and the ability to activate the hypoxia-inducible factor-1(HIF-1α)-erythropoietin(EPO) signal pathway. Pyruvate preserves glucose metabolism and cellular energetics better than bicarbonate, lactate, acetate and malate in the efficient correction of hypoxic lactic acidosis and shows few side effects. Therefore, application of pyruvate may be promising and safe as a novel therapeutic strategy in hypoxic lactic acidosis correction accompanied with multi-organ protection in critical care patients.
基金Grants from the research projects in Liaoning Province Science and Technology Department,No.2007225017,No.2009225011-2 and No.2011415052Science and Technology projects in Shenyang City,No.F11-264-1-19
文摘AIM:To investigate the expression and prognostic role of pyruvate dehydrogenase(PDH) in gastric cancer(GC).METHODS:This study included 265 patients(194 male,71 female,mean age 59 years(range,29-81 years) with GC who underwent curative surgery at the First Affiliated Hospital of China Medical University from January 2006 to May 2007.All patients were followed up for more than 5 years.Patient-derived paraffin embedded GC specimens were collected for tissue microarrays(TMAs).We examined PDH expression by immunohistochemistry in TMAs containing tumor tissue and matched nonneoplastic mucosa.Immunoreactivity was evaluated independently by two researchers.Overall survival(OS) rates were determined using the Kaplan-Meier estimator.Correlations with other clinicopathologic factors were evaluated by two-tailed χ2 tests or a two-tailed t-test.The Cox proportional-hazard model was used in univariate analysis and multivariate analysis to identify factors significantly correlated with prognosis.RESULTS:Immunohistochemistry showed that 35.47% of total cancer tissue specimens had cytoplasmic PDH staining.PDH expression was much higher in normal mucosa specimens(75.09%;P = 0.001).PDH expression was correlated with Lauren grade(70.77% in intestinal type vs 40.0% in diffuse type;P = 0.001),lymph node metastasis(65.43% with no metastasis vs 51.09% with metastasis;P = 0.033),lymphatic invasion(61.62% with no invasion vs 38.81% with invasion;P = 0.002),histologic subtypes(70.77% in intestinal type vs 40.0% in diffuse type;P = 0.001) and tumor-node-metastasis(TNM) stage(39% in poorly differentiated vs 65.91% in well differentiated and 67.11% in moderately differentiated;P = 0.001) in GC.PDH expression in cancer tissue was significantly associated with higher OS(P < 0.001).The multivariate analysis adjusted for age,Lauren classification,TNM stage,lymph node metastasis,histological type,tumor size,depth of invasion and lymphatic invasion showed that the PDH expression in GC was an independent prognostic factor for higher OS(HR = 0.608,95%CI:0.504-0.734,P < 0.001).CONCLUSION:Our study indicated that PDH expression is an independent prognostic factor in GC patients and that positive expression of PDH may be predictive of favorable outcomes.
基金supported by the the National Natural Science Foundation of China (30600439)
文摘To assess the effects ofcreatine pyruvate (Cr-Pyr) on lipid and protein metabolism in broiler chickens, a total of 400 1-day-old male birds (Aconred) were randomly allocated to four groups, with each group replicating four times and each replicate involving 25 birds. The broilers were provided with a commercial diet supplemented with Cr-Pyr at 0, 1, 5, or 10% of the diet, respectively, for a period of 3 wk ad libitum (from 22 to 42 d). In the present study, body weight (BW) and average daily gain (ADG) of broilers decreased in 10% Cr-Pyr group (P〈0.01), whereas the relative leg and pectoral muscle weights were significantly higher than they were in the control group (P〈0.05). 5 or 10% Cr-Pyr of diets decreased the abdominal fat rate (AFR, abdominal fat/live weight) of the broilers. The serum or hepatic triglyceride (TG) concentrations were significantly lower in the 5 and 10% groups (P〈0.01). In contrast, Cr-Pyr caused a marked increase in the serum nonesterified fatty acid (NEFA), high-density lipoprotein cholesterol (HDL-C) and creatine kinase (CK) concentrations (P〈0.01). Supplementation with Cr-Pyr (5 and 10%) in the diet also increased glucagons (GLU), insulin (INS) or leptin (LEP) contents (P〈0.01). The expression of hepatic peroxisomal proliferators-activated receptor α (PPAR-α) and carnitine palmitoyl transferase-I (CPT-I), muscle insulin-like growth factor I (IGF-I) were significantly elevated and myostatin mRNA level was reduced in the 5 and 10% groups (P〈0.05). It was found that supplementation with 5% Cr-Pyr improves both lipid and protein metabolism by regulating various metabolic parameters of broilers, while not adversely affects growth performance in broiler chickens.
基金supported by the grants from ‘San Ming’ Project of Shenzhen city,China(No.SZSM201612051)Municipal Health Planning Commission Fund of Shenzhen city,China(No.201601004,No.SZXJ2017078 and No.SXZJ2018084)
文摘Gastrointestinal(GI) cancer is one of the most common causes of cancer-related deaths worldwide.Tumor markers are valuable in detecting post-surgical recurrence or in monitoring response to chemotherapy.Pyruvate kinase isoform M2(PKM2),a glycolytic enzyme catalyzing conversion of phosphoenolpyruvate(PEP) to pyruvate,confers a growth advantage to the tumor cells and enables them to adapt to the tumor microenvironment.In this review,we have summarized current research on the expression and regulation of PKM2 in tumor cells,and its potential role in GI carcinogenesis and progression.Furthermore,we have also discussed the potential of PKM2 as a diagnostic and screening marker,and a therapeutic target in GI cancer.
基金supported by NIH grants 4R00DE 018400 to Jens Kreth
文摘The objective of this study was to characterize the oxygen dependent regulation of pyruvate oxidase (SpxB) gene expression and protein production in Streptococcus sanguinis (S. sanguinis). SpxB is responsible for the generation of growth-inhibiting amounts of hydrogen peroxide (H202) able to antagonize cariogenic Strepto- coccus mutans (S. mutans). Furthermore, the ecological consequence of H202 production was investigated in its self-inhibiting ability towards the producing strain. Expression of spxB was determined with quantitative Real-Time RT-PCR and a fluorescent expression reporter strain. Protein abundance was investigated with FLAG epitope engineered in frame on the C-terminal end of SpxB. Self inhibition was tested with an antagonism plate assay. The expression and protein abundance decreased in cells grown under anaerobic conditions. S. sanguinis was resistant against its own produced H202, while cariogenic S. mutans was inhibited in its growth. The results suggest that S. sanguinis produces H202 as antimicrobial substance to inhibit susceptible niche competing species like S. mutans during initial biofilm formation, when oxygen availability allows for spxB expression and Spx production.
基金supported in part by a USDA NIFA Postdoctoral Fellowship Grant(Award No.2011-67012-30684)
文摘Background: Salmonella enter/ca serovar Typhimurium is a major foodborne pathogen worldwide. S. Typhimurium encodes type III secretion systems via Salmonella pathogenicity islands (SPI), producing the major effector proteins of virulence. Previously, we identified two genes of Salmonella pyruvate metabolism that were up-regulated during chicken cell infection: pyruvate formate lyase I (pf/B) and b/functional acetaldehyde-CoA/alcohol dehydrogenase (adhE). We were therefore interested in examining the role these genes may play in the transmission of Salmonella to humans. Methods: Mutant strains of Salmonella with single gene deletions for pflB and adhE were created. Invasion and growth in human HCT-8 intestinal epithelial cells and THP-1 macrophages was examined. Quantitative PCR was performed on 19 SPI-1 genes. Results: In HCT-8 cells, both mutant strains had significantly higher intracellular counts than the wild-type from 4 to 48 h post-infection. Various SPI-1 genes in the mutants were up-regulated over the wild-type as early as 1 h and lasting until 24 h post-infection. In THP-1 cells, no significant difference in internal Salmonella counts was observed; however, SPI-1 genes were largely down-regulated in the mutants during the time-course of infection. We also found five SPI-1 genes - hilA, hiIC hill), sicP and rtsA - which were up-regulated in at least one of the mutant strains in log-phase broth cultures alone. We have therefore identified a set of SPI-1 virulence genes whose regulation is effected by the central metabolism of Salmonella.
基金The project is partially supported by the Natural Science Foundation of Hubei Province Contract(No.2003ABA072)
文摘Modification of transition metal cations to polymer-stabilized Pt colloidal clusters modified with cinchonidine was studied in enantioselective hydrogenation of methyl pyruvate.Compared to the enantiomeric excess(e.e.)value(71.4%) obtained without the presence of metal cations,obvious e.e.enhancement(up to 82.5%)was resulted from the addition of Zn^(2+) but with a certain decrease in activity.The reaction parameters in the presence of Zn^(2+) were also studied.It was found that the Pt colloidal catalysts in the presence of metal cations performed very differently from that in the absence of metal cations.
文摘Pyruvate, orthophosphate dikinase (PPDK) and phosphoenolpyruvate synthetase (PEPS) catalyze the conversion of pyruvate to phosphoenolpyruvate (PEP). Both are regulated by a phosphorylation-dephosphorylation mechanism involving a bifunctional serine/ threonine kinase and a pyrophosphorylase (PPDK regulatory protein, PDRP, and PEPS regulatory protein, PSRP, respectively). In plants the regulatory mechanism involves phosphorylation of a threonine residue that is separated by a single amino acid from the histidine residue that forms a phosphorylated intermediate during catalysis. Using antibodies, we demonstrated that the regulation of both Listeria monocytogenes PPDK and Escherichia coli PEP synthetase involves the phosphorylation of a threonine residue located close to the catalytic histidine residue. The amino acid located between the regulatory threonine and the catalytic histidine is highly conserved being serine in PPDK and cysteine in PEPS. Using site-directed mutagenesis we have shown that both PPDK and PEPS in which the serine and cysteine residues, respectively, were substituted with an alanine the enzymes could be regulated indicating that the serine and cysteine residues, respectively, are not essential for regulation. We also demonstrated that altering the intermediate amino acid did not alter the specificity of the regulatory proteins for their protein substrates.
文摘The polysaccharide was isolated from Hypnea pannosa which was grown in Okinawa, Japan. The yield of the polysaccharide was 17.2%, and the total carbohydrates, pyruvic acid, sulfuric acid and ash contents were 55.2%, 3.8%, 35.2% and 24.3%, respectively. 3,6-Anhydro-α-D-galactose, β-D-galactose, α-D-galactose and D-glucose were identified by liquid and thin-layer chromatography. Fourier transform infrared (FTIR) spectra of the polysaccharide resembled that of ι-carrageenan. From the <sup>1</sup>H- and <sup>13</sup>C-NMR spectra, 1,3-linked β-D-galactose, 1,4-linked anhydro-α-D-galactose, 1,4-linked α-D-galactose, 1,4-linked β-D-glucose and pyruvic acid (carboxyl acetal, methyl proton and methyl carbon) were assigned. Methylation analysis revealed terminal D-galactose 0.1 mol), 1,4-linked D-glucose (1.0 mol) and 1,2,3,4,6-linked D-galactose (3.7 mol) for native polysaccharide, and terminal D-galactose, 1,4-linked D-galactose (1.9 mol), 1,4-linked D-glucose (1.0 mol), 1,3- linked D-galactose (1.7 mol), and 1,3,4,6-linked D-galactose (0.3 mol) which substituted with pyruvate group at 4 and 6 positions for desulfated polysaccharide. The polysaccharide was the novel pyruvated glucogalactan sulfate, the structure of which was proposed.
文摘A novel method of preparing pyruvate from DL-lactate catalyzed by enzymes from a bacterial strain of Pseudomonas sp. SM-6 was proposed. Catalytic processes of cell-free extract enzymes and immobilized enzymes were evaluated. The kinetic data were studied, too.
文摘Pyruvate was produced from DL-lactate by a kind of green-chemical biocatalyst cell-free extract from bacterial strain Pseudomonas sp. SM-6. Catalase in cell-free extract, which could stabilize the pyruvate formed by lactate oxidase, played an important role in pyruvate preparation. The effect of catalase in conversion process was evaluated.
基金Supported by the National Natural Science Foundation of China
文摘Pyruvate, a final metabolite of glycogen, is widely distributed over many kinds of tissue fluids of human bodys. The determination for its contents is of clinical importance in gynaecology. Titrimetry, colorimetry and chromatography are common used methods. In recent years, enzymatic mthod has proved to be one of the most important determination techniques for its simplicity and fastness. However, in some cases, the use of purified enzymes as biocatalysts yields systems with a short useful lifetime owing, to enzyme instability A tiss
文摘The kinetics of oxidation of pyruvate by diperiodatoargentate( III) ion (DPA) has been studied spec-trophotometrically in alkaline medium. It was found that the reaction order with respect to both DPA and pyruvate is unity and the rate equation can be expressed asThe rate increases with the increase in [OH ] and decreases with the increase in [periodate]. There is a positive ionic strength effect in this reaction system. A mechanism has been proposed to explain the experimental results. The observed activation parameters are presented.
文摘BACKGROUND The understanding regarding genetic variation,pathophysiology,and complications associated with pyruvate kinase deficiency(PKD)in red blood cells has been explained largely,and supportive treatment is currently the main management strategy.Etiotropic managements,including transplantation and genome editing,supplying for substitute dugs of the pyruvate kinase,are all under research.CASE SUMMARY We herein report a 3-year-old boy with severe transfusion-dependent PKD cured by unrelated identical peripheral blood stem cell transplantation(PBSCT).Hemoglobin was corrected to a normal level by gene correction after PBSCT,with no complication related to the transplantation.CONCLUSION Hematopoietic stem cell transplantation could be a substitute for transfusiondependent PKD.
文摘The purpose of this study is to investigate the perioperative changes of erythrocyte kinase (PK) activity. Thirty patients undergoing upper abdominal surgery were dirided into epidural blockade(EB) group or intra venous procaine balanced anesthesia(IPBA) group. The blood level of glucose increased significantly at 60 min after the beginning of operations in both groups. Blood glucose levels on the first postoperative day were significantly higher than the baselines in both groups [(8. 29±1. 5)vs (4. 8±0.18) mmol/L (P< 0.01) in EB, (6.36±0.33) vs (4. 55±0.18 ) mmol/L (P<0. 01 ) in IPBA]. The concentrations of 2, 3-DPG in RBC were not significantly changed in both groups. The PK activity in RBC decreased signficantly at 60 min after the end of operation in both groups. The PK activity levels on the first postoperative day were significantly lower than the baselines in both groups [(7. 59±1. 01) vs (11. 62±1. 06) IU/gHb (P<0. 05) in EB; (7. 75±0. 94) vs (11. 84 ±1.12) IU/gHb (P<0. 05 ) in IPBA]. The results suggest that the PK activity is decreased and the concentration of 2, 3-DPG remians unchanged under the hyperglycemic response to surgical stress, which may be related to an inhibition of glycolysis in RBC.