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Detection of LAMA2 c.715C>G:p.R239G mutation in a newborn with raised creatine kinase: A case report
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作者 Jing Yuan Xiang-Ming Yan 《World Journal of Clinical Cases》 SCIE 2024年第14期2445-2450,共6页
BACKGROUND We report a rare case of primary clinical presentation featuring elevated creatine kinase(CK)levels in a neonate,which is associated with the LAMA2 gene.In this case,a heterozygous mutation in exon5 of the ... BACKGROUND We report a rare case of primary clinical presentation featuring elevated creatine kinase(CK)levels in a neonate,which is associated with the LAMA2 gene.In this case,a heterozygous mutation in exon5 of the LAMA2 gene,c.715C>G(resulting in a change of nucleotide number 715 in the coding region from cytosine to gua-nine),induced an amino acid alteration p.R239G(No.239)in the patient,repre-senting a missense mutation.This observation may be elucidated by the neonatal creatine monitoring mechanism,a phenomenon not previously reported.CASE SUMMARY We analysed the case of a neonate presenting solely with elevated CK levels who was eventually discharged after supportive treatment.The chief complaint was identification of increased CK levels for 15 d and higher CK values for 1 d.Ad-mission occurred at 18 d of age,and despite prolonged treatment with creatine and vitamin C,the elevated CK levels showed limited improvement.Whole exo-me sequencing revealed the presence of a c.715C>G mutation in LAMA2 in the newborn,correlating with a clinical phenotype.However,the available informa-tion offers insufficient evidence for clinical pathogenicity.CONCLUSION Mutations in LAMA2 are associated with the clinical phenotype of increased neonatal CK levels,for which no specific treatment exists.Whole genome sequen-cing facilitates early diagnosis. 展开更多
关键词 creatine kinase LAMA2 Gene mutation NEONATE Case report
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Oligosaccharide and Creatine Supplementation on Glucose and Urea Nitrogen in Blood and Serum Creatine Kinase in Basketball Athletes
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作者 石大玲 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2005年第5期587-589,共3页
Summary: The effects of oligosaccharide and creatine (Cr) supplementation on glucose, lactic acid and urea nitrogen levels in blood and activity of serum creatine kinase (CK) were explored. Twenty CUBA male athle... Summary: The effects of oligosaccharide and creatine (Cr) supplementation on glucose, lactic acid and urea nitrogen levels in blood and activity of serum creatine kinase (CK) were explored. Twenty CUBA male athletes were divided into 4 groups: group A (supplementation of Cr alone), group B (supplementation of oligosaccharide), group C (supplementation of oligosaccharide and Cr) and group D (placebo control group). By using orthogonal L4 table (2a ), the experiment was performed. There were factors including oligosaccharide (carbohydrate, CHO), Cr and their correlation. Each factor had two levels: supplementation and no-supplementation. The results showed that the supplementation of CliO or Cr alone, combined supplementation of CHO and Cr could significantly reduce the glucose, urea nitrogen levels in blood and serum CK activity after competition in the athletes. Moreover, the effects of combined supplementation of CHO and Cr were more satisfactory. It was concluded that supplementation of CliO and Cr could promote the recovery of physical performance and athletic abilities after athletics in basketball athletes. 展开更多
关键词 OLIGOSACCHARIDE creatine blood glucose blood urea nitrogen serum creatine kinase BASKETBALL ATHLETE
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Relationship Between Serum Creatine Kinase Isoenzyme MM Subbands and the Gradation of Coronary Stenosis in Patients with Unstable Angina Pectoris
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作者 吴自强 祝善俊 +1 位作者 孟素荣 孙月和 《South China Journal of Cardiology》 CAS 2000年第1期28-31,共4页
Objective To observe the relationship between serum creatine kinase isoenzyme MM sub-bands (CKMM3/MM1 ratio) and the gradation of coronary stenosis and provide a simple, reliable, and economical method for identifying... Objective To observe the relationship between serum creatine kinase isoenzyme MM sub-bands (CKMM3/MM1 ratio) and the gradation of coronary stenosis and provide a simple, reliable, and economical method for identifying high-risk unstable angina pectoris (UAP). Mehtods Blood samples were drawn at different time after onset of chest pain in 21 patients with UAP and only once in 20 each volunteers for control. CKMM3/MM1 ratio was detected by nonserial buffer agarose gel electrophoresis. CKMB and CK were observed by velocity method. An emergent coronary arteriography was performed as soon as patients were admitted into hospital. Results Patients with UAP were divided into two subgroups: patients with elevated serum enzyme [P( + )] and patients with normal serum enzyme [P( - ) ] according to CKMM3/MM1 ratio < 0. 5. Patients with UAP( + ) had higher serum CKMM3/MM1 ratios from 0.5 to 12hrs and serum CKMB from 2 to 12 hrs than those with UAP( - ) and control ( P < 0. 05) . Serum enzyme concentrations of patients with UAP whose coronary lumen had 90% or more than 90% stenosis were significantly higher than those whose coronary lumen had less than 90% stenosis ( P <0. 01) . Any CK-MM3/MM1 ratio was less than 1. 0 and CK within the normal range in patients with UAP( + ) group. Conclusions CKMM3/MM1 ratios in patients with UAP can reflect severity of myocardial ischemia. SerumCKMM3/MM1 ratio provides a simple, reliable, and economical method for identifying high-risk UAP. 展开更多
关键词 Unstable angina pectoris creatine kinase isoenzyme MMsubbands Coronary stenosis
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American ginseng supplementation attenuates creatine kinase level induced by submaximal exercise in human beings 被引量:7
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作者 Cheng-Chen Hsu Min-Chen Ho +2 位作者 Li-Chin Lin Borcherng Su Mei-Chich Hsu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2005年第34期5327-5331,共5页
AIM: To investigate whether American ginseng (AG, Panax quinquefolium) supplementation was able to improve endurance exercise performance.METHODS: Thirteen physically active male college students were divided into two... AIM: To investigate whether American ginseng (AG, Panax quinquefolium) supplementation was able to improve endurance exercise performance.METHODS: Thirteen physically active male college students were divided into two groups (AG or placebo)and received supplementation for 4 wk, before the exhaustive running exercise. Treadmill speed was increased to a pace equivalent to 80% VO2max of the subject. A 4-wk washout period followed before the subjects crossed over and received the alternate supplement for the next 4 wk.They then completed a second exhaustive running exercise. The physiological variables that were examined included time to exhaustion and oxygen pulse. Moreover,the plasma creatine kinase (CK) and lactate were measured prior to the exercise, at 15 and 30 min during exercise,immediately after exercise, and 20, 40, 60, and 120 min after exercise.RESULTS: The major finding of this investigation was that the production plasma CK during the exercise significantly decreased for group AG than for group P. Secondary physiological finding was that 80% VO2max running was not improved over a 4-wk AG supplementation regimen.CONCLUSION: Supplementation with AG for 4 wk prior to an exhaustive aerobic treadmill running reduced the leakage of CK during exercise, but did not enhance aerobic work capacity. The reduction of plasma CK may be due to the fact that AG is effective for the decrease of skeletal muscle cell membrane damage, induced by exercise during the high-intensity treadmill run. 展开更多
关键词 Panax quinquefoflum American ginseng creatine kinase Endurance exercise
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Creatine kinase in the diagnosis and prognostic prediction of amyotrophic lateral sclerosis:a retrospective case-control study 被引量:1
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作者 Xue-Ping Chen Qian-Qian Wei +8 位作者 Ru-Wei Ou Yan-Bing Hou Ling-Yu Zhang Xiao-Qin Yuan Yun-Qian Yao De-Sheng Jia Qian Zhang Wei-Xue Li Hui-Fang Shang 《Neural Regeneration Research》 SCIE CAS CSCD 2021年第3期591-595,共5页
Creatine kinase is a muscle enzyme that has been reported at various levels in different studies involving patients with amyotrophic lateral sclerosis.In the present retrospective case-control study,we included 582 pa... Creatine kinase is a muscle enzyme that has been reported at various levels in different studies involving patients with amyotrophic lateral sclerosis.In the present retrospective case-control study,we included 582 patients with amyotrophic lateral sclerosis and 582 age-and sexmatched healthy controls.All amyotrophic lateral sclerosis participants received treatment in the Department of Neurology,West China Hospital,China,between May 2008 and December 2018.Serum creatine kinase levels in patients with amyotrophic lateral sclerosis were significantly higher than those in healthy controls.Subgroup analysis revealed that serum creatine kinase levels in men were higher than those in women in both amyotrophic lateral sclerosis patients and healthy controls.Compared with patients with bulbar-onset amyotrophic lateral sclerosis,patients with limb-onset amyotrophic lateral sclerosis had higher creatine kinase levels.Spearman's correlation analysis revealed that serum creatine kinase levels were not correlated with body mass index,Amyotrophic lateral Sclerosis Functional Rating ScaleRevised score,or progression rate.After adjusting for prognostic covariates,higher log creatine kinase values were correlated with higher overall survival in the amyotrophic lateral sclerosis patients.We also investigated the longitudinal changes in serum creatine kinase levels in 81 amyotrophic lateral sclerosis patients;serum creatine kinase levels were decreased at the second blood test,which was sampled at least 6 months after the first blood test.Together,our results suggest that serum creatine kinase levels can be used as an independent factor for predicting the prognosis of amyotrophic lateral sclerosis patients.This study received ethical approval from the Ethics Committee of West China Hospital,China(approval No.2015(236))on December 23,2015. 展开更多
关键词 amyotrophic lateral sclerosis BIOMARKER creatine kinase DIAGNOSIS epidemiological study prognosis SEROLOGY survival
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Flunarizine and lamotrigine prophylaxis effects on neuron-specific enolase, S-100, and brain-specific creatine kinase in a fetal rat model of hypoxic-ischemic brain damage
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作者 Li He Jingyi Deng Wendan He 《Neural Regeneration Research》 SCIE CAS CSCD 2008年第7期768-771,共4页
BACKGROUND: Calcium antagonists may act as neuroprotectants, diminishing the influx of calcium ions through voltage-sensitive calcium channels. When administered prophylactically, they display neuroprotective effects... BACKGROUND: Calcium antagonists may act as neuroprotectants, diminishing the influx of calcium ions through voltage-sensitive calcium channels. When administered prophylactically, they display neuroprotective effects against hypoxic-ischemic brain damage in newborn rats. OBJECTIVE: To investigate the neuroprotective effects of flunarizine (FNZ), lamotrigine (LTG) and the combination of both drugs, on hypoxic-ischemic brain damage in fetal rats. DESIGN AND SETTING: This randomized, complete block design was performed at the Department of Pediatrics, Shenzhen Fourth People's Hospital, Guangdong Medical College. MATERIALS: Forty pregnant Wistar rats, at gestational day 20, were selected for the experiment and were randomly divided into FNZ, LTG, FNZ + LTG, and model groups, with 10 rats in each group. METHODS: Rats in the FNZ, LTG, and FNZ + LTG groups received intragastric injections of FNZ (0.5 mg/kg/d), LTG (10 mg/kg/d), and FNZ (0.5 mg/kg/d) + LTG (10 mg/kg/d), respectively. Drugs were administered once a day for 3 days prior to induction of hypoxia-ischemia. Rats in the model group were not administered any drugs. Three hours after the final administration, eight pregnant rats from each group underwent model establishment hypoxia-ischemia brain damage to the fetal rats. Cesareans were performed at 6, 12, 24, and 48 hours later; and 5 fetal rats were removed from each mother and kept warm. Two fetuses without model establishment were removed by planned cesarean at the same time and served as controls. A total of 0.3 mL serum was collected from fetal rats at 6, 12, 24, and 48 hours, respectively, following birth. MAIN OUTCOME MEASURES: Serum protein concentrations of neuron-specific enolase and S-100 were measured by ELISA. Serum concentrations of brain-specific creatine kinase were measured using an electrogenerated chemiluminescence method. RESULTS: Serum concentrations of neuron-specific enolase, S-100, and brain-specific creatine kinase were significantly higher in the hypoxic-ischemic fetal rats, compared with the non-hypoxic-ischemic group. Serum concentrations of neuron-specific enolase, S-100, and brain-specific creatine kinase were significantly less in the FNZ, LTG, and FNZ + LTG groups following ischemia, compared with the model group (P 〈 0.01). However, these values were significantly greater in the FNZ and LTG groups, compared with the FNZ + LTG group, following ischemia (P 〈 0.01). CONCLUSION: Preventive antenatal use of oral FNZ and LTG has positive neuroprotective effects on intrauterine hypoxic-ischemic brain damage. The combined effect of these two drugs is superior. 展开更多
关键词 FLUNARIZINE LAMOTRIGINE hypoxic-ischemic brain damage neuron-specific enolase S-100 brain-specific creatine kinase
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RXPERIMENTAL AND CLINICAL STUDY OF CREATINE KINASE BB ACTIVITY FOR THE DIAGNOSIS ON BRAIN DAMAGE
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作者 师蔚 王芳茹 +6 位作者 周任 孙建军 巩守平 刘重霄 高李贵 屈建强 周乐 《Academic Journal of Xi'an Jiaotong University》 2001年第2期113-115,共3页
Objective To study the differential diagnosis on cerebral concussion and mild cerebral contusion value of the brain type creatine kinase isoenzyme(CK BB),and evaluate the seriousness of brain damage and prognosis of t... Objective To study the differential diagnosis on cerebral concussion and mild cerebral contusion value of the brain type creatine kinase isoenzyme(CK BB),and evaluate the seriousness of brain damage and prognosis of the patients with acute head injury.Methods Chromatographic separating and fluorometric quantifying technique was used to detect the CK BB activity in the cerebrospinal fluid(CSF) of 117 patients with acute head injury and 12 patients with increased intracranial pressure and 20 normal people.Results The CSF CK BB activity of the patients with acute head injury was remarkably higher than that of the normal people and the CSF CK BB activity increased with the seriousness of brain damage.There was a close relationship between CSF CK BB activity and prognosis,and higher activity of CSF CK BB indicated poor prognosis.Conclusion CSF CK BB activity could be used as a new index to diagnose brain damage and evaluate the seriousness of brain damage and prognosis. 展开更多
关键词 head injury cerebrospinal fluid creatine kinase isoenzyme DIAGNOSIS
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Comparison of serum cardiac troponin-Ⅰ and creatine kinase MB isoenzyme concentrations in asphyxiated neonates
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作者 Nouran F. Hussien Eman A. Abdel Ghany +2 位作者 Amany E.Elwan Yasser H.Kamel Dina K.Ali 《海南医学院学报》 CAS 2009年第1期31-36,共6页
Objective:To assess the correlation of signs of myocardial damage to serum cardiac troponin I(cTnI)and creatine kinase MB isoenzyme(CK-MB)concentrations.Methods:Blood samples were collected from 25 term asphyxiated ne... Objective:To assess the correlation of signs of myocardial damage to serum cardiac troponin I(cTnI)and creatine kinase MB isoenzyme(CK-MB)concentrations.Methods:Blood samples were collected from 25 term asphyxiated neonates and 25 controls at 12 h of age by immunoassay.The asphyxiated neonates were followed up until discharge or death.Results:Asphyxiated neonates had significantly higher concentrations of cTnI and CK-MB than controls(P<0.001).Serum cTnI concentrations were significantly higher in asphyxiated neonates who developed hypotension,heart failure or those had low ejection fraction(P<0.01).Serum cTnI concentrations were significantly higher in asphyxiated who died than those who survived(P<0.01).There was no significant difference in serum CK-MB mass concentrations between asphyxiated neonates with and without these complications.Conclusion:Unlike CK-MB,serum cTnI concentrations are significantly higher in asphyxiated neonates who died or developed cardiac dysfunction. 展开更多
关键词 肌钙蛋白 肌酸激酶 围产期 心脏水肿
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穴位灸法对运动时机体血清CK、BLA及运动能力的影响 被引量:33
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作者 史曙生 《南京师大学报(自然科学版)》 CAS CSCD 2002年第1期103-107,共5页
通过对运动员进行穴位施灸处理 ,并以西洋参作为对照 ,观察定量运动时血清CK(肌酸激酶 )及BLA(血乳酸 )含量的变化以及台阶指数的变化 .经过 2个月的施灸处理 ,结果表明艾灸可以明显降低运动时机体血清肌酸激酶 (CK)的活性及血乳酸的含... 通过对运动员进行穴位施灸处理 ,并以西洋参作为对照 ,观察定量运动时血清CK(肌酸激酶 )及BLA(血乳酸 )含量的变化以及台阶指数的变化 .经过 2个月的施灸处理 ,结果表明艾灸可以明显降低运动时机体血清肌酸激酶 (CK)的活性及血乳酸的含量 ,能明显提高机体的台阶指数 .本研究提示 :灸法可以减轻运动性疲劳 ,提高机体的运动能力 . 展开更多
关键词 穴位灸法 机体血清 CK blA 运动能力 艾灸 肌酸激酶 血乳酸 台阶指数 运动性疲劳
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Studies on the creatine kinase MM isoforms of normal and Duchenne muscular dystrophic patients 被引量:3
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作者 赵昕 毕春雷 杨振华 《Chinese Medical Journal》 SCIE CAS CSCD 1998年第1期75-77,共3页
OBJECTIVE: To study the changes of creatine kinase MM (CK-MM) isoforms in Duchenne muscular dystrophy (DMD) patients. METHODS: Serum samples from 49 DMD patients and 40 control subjects were collected for CK-MM isofor... OBJECTIVE: To study the changes of creatine kinase MM (CK-MM) isoforms in Duchenne muscular dystrophy (DMD) patients. METHODS: Serum samples from 49 DMD patients and 40 control subjects were collected for CK-MM isoforms measurement. CK-MM isoforms were separated within 30 minutes by electrophoresis on agarose gel with a discontinuous buffer system at constant current of 30 mA and low voltage of 200-300 V, then measured by fluorescence scanning. RESULTS: Significant differences of MM2/MM1 ratio were found between DMD patients and control subjects (P 展开更多
关键词 Adolescent Adult Biological Markers CHILD Child Preschool creatine kinase Electrophoresis Agar Gel Female Humans ISOENZYMES Male Muscular Dystrophies
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RELATIONS OF INTRACRANIAL PRESSURE, CREATINE KINASE AND BRAINSTEM AUDITORY EVOKED POTENTIAL IN PATIENTS WITH TRAUMATIC BRAIN EDEMA 被引量:9
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作者 王维平 裘明德 +1 位作者 任海军 张星虎 《Chinese Medical Journal》 SCIE CAS CSCD 1994年第3期47-50,共4页
We studied the relations of intracranial pressure (ICP),creatine kinase (CK) and bralnstem auditory evoked potential (BAEP) in 44 patients with traumatic brain edema who were admitted to our hospital from June 1990 to... We studied the relations of intracranial pressure (ICP),creatine kinase (CK) and bralnstem auditory evoked potential (BAEP) in 44 patients with traumatic brain edema who were admitted to our hospital from June 1990 to February 1991. There were 30 males and 14 females, with age range from 9 to 67 years. The results showed that the abnormal BAEP could reflect the severity of cerebral edema in acute head injury and was related to ICP and serum CK levels. When ICP>30 mmHg (4kPa), the abnormality of BAEP was more obvious than that of the control group (P<0.05); the serum CK levels were also elevated markedly. In patients with ICP over and below 4kPa, the rate of abnormal BAEP was 38.46% and 77.78% respectively (P<0.05). The serum CK level in the normal group or in the group with moderate abnormality of BAEP was significantly different from that in the group with severe abnormality or lack of BAEP (274.8± 98.24 U/L vs 705.3± 364.27 U/L; P<0.001). After treatment, the ICP returned to normal, and the BAEP norm 展开更多
关键词 ICP BAEP creatine kinase AND BRAINSTEM AUDITORY EVOKED POTENTIAL IN PATIENTS WITH TRAUMATIC BRAIN EDEMA RELATIONS OF INTRACRANIAL PRESSURE
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Amplified fluorescence of Mg^2+ selective red-light emitting carbon dot in water and direct evaluation of creatine kinase activity 被引量:3
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作者 Saptarshi Mandal Jagannath Pal +1 位作者 Ranga Subramanian Prolay Das 《Nano Research》 SCIE EI CAS CSCD 2020年第10期2770-2776,共7页
Carbon quantum dot/carbon dot(CD)exhibiting sustained photoluminescence at longer wavelengths in aqueous solution is difficult to prepare,but has enormous potential in biomedical applications.For the first time,we rep... Carbon quantum dot/carbon dot(CD)exhibiting sustained photoluminescence at longer wavelengths in aqueous solution is difficult to prepare,but has enormous potential in biomedical applications.For the first time,we report the magnesium(II)selective fluorescence enhancement of a red-light emitting anthrarufin and boric acid-derived CD in aqueous solution for direct evaluation of creatine kinase(CK)enzyme activity.The CD displayed visually detectable,intense red fluorescence only in the presence of magnesium ion(Mg^2+)at physiological pH value when irradiated with an ultraviolet(UV)source.Concurrently,a significant increase in steady-state fluorescence intensity and fluorescence lifetime was documented.A time-dependent density functional theory(TD-DFT)analysis displayed a bathochromic shift in UV–visible(vis)absorption,and increased oscillator strength of transition resulting from the selective chelation of Mg^2+withβ-hydroxy keto functionality on the surface of the CD.The CD–Mg^2+assembly was subsequently used to conceptualize the detection of CK directly through the exploration of the differential binding affinity of Mg2+with adenosine triphosphate(ATP),adenosine diphophate(ADP),and CD that is otherwise not possible with commercially available kits as of today.Thus,the report delineated here usher grandeur potential of CD for biological explorations related to Mg2+or ATP sensing and monitoring of Mg^2+-dependent enzymatic activity through a clear understanding of the chemistry. 展开更多
关键词 carbon dot(CD) Mg^2+indicator fluorescence amplification creatine kinase(CK) adenosine triphosphate(ATP)
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Refolding of OPTA-labeled creatine kinase denatured by guanidinium chloride
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作者 汤震宇 周海梦 《Chinese Science Bulletin》 SCIE EI CAS 1995年第19期1642-1646,共5页
Although refolding of fully denatured protein molecules in vitro is not a valid model of folding of the nascent peptide chain in a biologically active protein in vivo, it can provide some useful information for protei... Although refolding of fully denatured protein molecules in vitro is not a valid model of folding of the nascent peptide chain in a biologically active protein in vivo, it can provide some useful information for protein folding. Therefore, refolding of denatured proteins has been extensively studied in recent years. It has been previously reported that during the refolding of guanidine or urea denatured creatine kinase, the enzymatic activity and the na- 展开更多
关键词 creatine kinase DENATURATION CHEMICAL MODIFICATION refolding.
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INACTIVATION OF CREATINE KINASE AT LOW GUANIDINE CONCENTRATIONS IS NOT DUE TO THE DISSOCIATION OF THE DIMERIC ENZYME
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作者 刘国华 侯立向 邹承鲁 《Chinese Science Bulletin》 SCIE EI CAS 1989年第12期1036-1040,共5页
Ⅰ. INTRODUCTIONIn earlier publications from this laboratory it has been reported that during the denaturation of creatine kinase (ATP: creatine phosphotransferase EC 2.7.3.2) by guanidine and urea, the inactivation o... Ⅰ. INTRODUCTIONIn earlier publications from this laboratory it has been reported that during the denaturation of creatine kinase (ATP: creatine phosphotransferase EC 2.7.3.2) by guanidine and urea, the inactivation of the enzyme takes place at denaturant concentrations much lower than necessary to bring about noticeable conformational changes as detected by conventional physicochemical, methods. Moreover, at the same denaturant concentration, the inactivation rates are several orders of magnitude 展开更多
关键词 creatine kinase GUANIDINE DIMERIC enzyme.
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Conformational Changes at the Active Site of Creatine Kinase During Denaturation of Urea
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作者 阴勇 王希成 周海梦 《Chinese Science Bulletin》 SCIE EI CAS 1993年第23期2001-2004,共4页
It has been previously reported that during the denaturation of creatine kinase (ATP: creatine phosphotransferase EC 2.7.3.2) by guanidine hydrochloride, urea or SDS, inactivation occurs before noticeable conformation... It has been previously reported that during the denaturation of creatine kinase (ATP: creatine phosphotransferase EC 2.7.3.2) by guanidine hydrochloride, urea or SDS, inactivation occurs before noticeable conformational change of the enzyme molecule as a whole can be detected, and the inactivation rate constants of the enzyme in the above denaturant solutions are several orders of magnitude faster than those of 展开更多
关键词 creatine kinase UREA DENATURATION active SITE chemical MODIFICATION conformational changes.
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Hydrolysis and Cyanolysis of DTNB-Modified Creatine Kinase
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作者 何飚 王洪睿 +1 位作者 王希成 周海梦 《Science China Chemistry》 SCIE EI CAS 1994年第9期1082-1089,共8页
The cyanolysis of DTNB-modified creatine kinase(S,S’-di-TNB-CK)has been studied.Itwas found that there exist both cyanolysis and hydrolysis at the same time under the cyanolysis condition de-scribed previously by Deg... The cyanolysis of DTNB-modified creatine kinase(S,S’-di-TNB-CK)has been studied.Itwas found that there exist both cyanolysis and hydrolysis at the same time under the cyanolysis condition de-scribed previously by Degani.DTNB-modified creatine kinase was rapidly hydrolyzed at pH 9.5 in the ab-sence of KCN.The hydrolysis shows biphasic kinetics as seen in the semilogarithmic pseudo-first-order rateplot.The analysis shows that about one S-TNB group/mol of DTNB-modified creatine kinase was rapidly re-leased in the fast phase of the hydrolysis reaction.The further cyanolysis of hydrolytic products showsmonophasic kinetics,and about one S-TNB group/mol of hydrolytic product was also rapidly released.Theabove results show that one of the two TNB-labeled thiol groups situated respectively at two active sites ofthe creatine kinase molecule was rapidly hydrolyzed,and the other was hydrolyzed at a very slow rate.Whenthe hydrolyzed products were cyanolyzed,the other residual TNB group was also released.These resultssuggest that the subunits of creatine kinase are asymmetrically associated.This leads to the differential envi-ronments of the two thiol groups at the active sites of two subunits.The above results also show that withthe TNB release during hydrolysis or cyanolysis,the enzymic activity was also partially recovered at the sametime.The recovery in activity is linearly related to the extent of the regeneration of reactive thiol groups.Therefore,it is suggested that the reactive thiol groups of enzyme are essential for its activity,and they arelocated in the active sites of dimeric enzyme. 展开更多
关键词 creatine kinase CHEMICAL MODIFICATION HYDROLYSIS cyanolysis
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2-Chloromercuri-4-nitrophenol-modified Sites of Creatine Kinase Confirmed by FPLC
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作者 张平城 《Science China Chemistry》 SCIE EI CAS 1994年第1期50-58,共9页
MNP-modified tryptic peptides of creatine kinase have been separated with two-dimensional electrophoresis, but the location of the SH groups of creatine kinase modified by MNP still seemed to be vague until recently (... MNP-modified tryptic peptides of creatine kinase have been separated with two-dimensional electrophoresis, but the location of the SH groups of creatine kinase modified by MNP still seemed to be vague until recently (Laue, M. C. & Quiocho, F. A. , 1977). Two peptides have now been found to be the MNP-modified peptides with reversed-phase FPLC methods, and the amino acid compositions of these two peptides are in agreement with those of the two peptides around Cys-145 and Cys-253, respectively. These findings indicate that the two buried SH groups of creatine kinase have been modified by MNP. 展开更多
关键词 creatine kinase. FPLC SH GROUPS chemical modification mercurial.
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Effects of Glycerol in the Refolding and Unfolding of Creatine Kinase
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作者 欧文斌 朴龙斗 +1 位作者 孟凡国 周海梦 《Tsinghua Science and Technology》 SCIE EI CAS 2002年第4期352-362,共11页
The effects of glycerol in the refolding, reactivation, unfolding, and inactivation of guanidine denatured creatine kinase were studied by observing the fluorescence emission spectra and the circular dichroism sp... The effects of glycerol in the refolding, reactivation, unfolding, and inactivation of guanidine denatured creatine kinase were studied by observing the fluorescence emission spectra and the circular dichroism spectra, and by recovery and inactivation of enzymatic activity and aggregation. The results show that low concentrations of glycerol (<25%) improve the refolding yields of creatine kinase, but high glycerol concentrations decrease its recovery. Glycerol favors the secondary structural formation and inhibits aggregation of creatine kinase as proline does. These systematic observations further support the suggestion that low concentrations of glycerol possibly play a chaperone role in the refolding of creatine kinase. In addition, glycerol reduces the inactivation and unfolding rate of creatine kinase, increases the change in transition free energy of unfolding (ΔΔG u) and stabilizes its active conformation relative to the partially unfolded state with no glycerol. In the presence of glycerol, the inactivation and unfolding dynamics of creatine kinase are related to glycerol concentrations. Glycerol blocks the exposure of hydrophobic areas and the dissociation of dimers, and protects creatine kinase against guanidine denaturation in a concentration dependent manner. This study suggests that glycerol as an energy substrate for metabolism and organic components in vivo, assists correct protein folding, maintains adequate rates of enzymatic catalysis and stabilizes the protein secondary and tertiary conformations. 展开更多
关键词 GLYCEROL creatine kinase UNFOLDING REFOLDING guanidine denaturation
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Kinetics of the Inactivation of Creatine Kinase During Inhibition by Planar Anions
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作者 张艳 陈培榕 +2 位作者 邹晓明 王希成 周海梦 《Science China Chemistry》 SCIE EI CAS 1993年第11期1315-1324,共10页
The kinetic theory of the substrate reaction during the modification of enzyme activity previously described by Tsou has been applied to a study on the kinetics of slow irreversible inhibition of creatine kinase by pl... The kinetic theory of the substrate reaction during the modification of enzyme activity previously described by Tsou has been applied to a study on the kinetics of slow irreversible inhibition of creatine kinase by planar anions. Kinetic equation of substrate reaction was derived according to the theoretical analysis and experiment data, and then was simplified. From the simplified equation for the substrate reaction in the presence of the inhibitors, the microscopic rate constants for the reaction of the inhibitors with enzyme were obtained. The mechanism of inhibition of enzyme activity was discussed. 展开更多
关键词 creatine kinase INHIBITION activity kinetics.
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Characterization of the Partially Folded Monomeric Intermediate of Creatine Kinase
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作者 朴龙斗 周海梦 《Tsinghua Science and Technology》 SCIE EI CAS 2002年第4期347-351,共5页
The importance of understanding the protein folding pathway and intermediates is well recognized on the basis of extensive studies of protein folding in vitro and in vivo. Creatine kinase (CK) is a typical model fo... The importance of understanding the protein folding pathway and intermediates is well recognized on the basis of extensive studies of protein folding in vitro and in vivo. Creatine kinase (CK) is a typical model for studying unfolding and refolding of proteins due to several interesting properties. Recent studies on the folding of CK show that its partially folded monomeric intermediate is present kinetically and is stable at equilibrium. The present paper contains 33 references as a mini review to characterize the properties of CK from studies on the CK folding pathway. Characterization of these intermediates is an essential step toward understanding the mechanism of protein folding. Some well determined schemes are suggested as protein folding models. 展开更多
关键词 creatine kinase INTERMEDIATE partially folded state folding pathway
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