Credible and Facile Fluorometric Detection of Soybean Trypsin Inhibitor Activity with a Water-Soluble Poly(diphenylacetylene) Derivative

Herein,a novel method for fl uorometric detection of soybean trypsin inhibitor(SBTI)activity based on a water-soluble poly(diphenylacetylene)derivative was reported.Fluorescence quenching of the polymer via p-nitroaniline,produced from the trypsin-catalyzed decomposition of N-benzoyl-DL-arginine-4-nitroanilide hydrochloride(L-BAPA),was well described using the Stern-Volmer equation.SBTI activity was quantitatively assessed based on changes in the fl uorescence intensity of the polymer.This strategy has several advantages,such as high sensitivity and ease of operation.Moreover,its applicability to other biochemical analyses is promising.

A Proteinase from Mung Bean Sprouts That Inactivaties Soybean Trypsin Inhibitor

By 30% - 60% (NH4)(2)SO4 fractional precipitation, anion-exchange chromatography on DEAE-Sepharose CL-6B, gel filtration on Sephacryl S-200 and anion-exchange chromatography on Waters AP-1 column (Protein(PM)-Pak DEAE 15HR), a proteinase which can inactivate soybean trypsin inhibitor (STI) was purified from mung bean ( Vigna rabiata (L.) Wilezek) sprouts. Its molecular weight was estimated to be 29.8 kD by SDS-PAGE, and its K-m and V-max for STI were 769.2 N-alpha -benzoyl-L-arginine ethyl ester BAEE/mL and 115.3 BAEE . mL(-1) . min(-1) respectively. This proteinase was stable at temperatures lower than 50 degreesC and pH 6.5 - 8.5, and 90.91% STI activity of defatted soybean powder was inactivated by this preparation, with proteolytic activity 5 000 BAEE/mL at 50 degreesC and pH 8.0 in 4 h.

Optimization of Solid-State Fermentation with Lactobacillus brevis and Aspergillus oryzae for Trypsin Inhibitor Degradation in Soybean Meal

The aim of the present study was to optimize trypsin inhibitor degradation in soybean meal by solid-state fermentation （SSF） with Lactobacillus brevis and Aspergillus oryzae, and to determine the effect of SSF on phytic acid, crude protein, crude fat, and amino acid profile. Response surface methodology （RSM） with Box-Behnken design was used to optimize SSF. The optimal conditions derived from RSM for L. brevis fermentation were： pH=5. 1; inoculum size=10%; duration=72 h; substrate to water ratio=1.5. The minimum content of trypsin inhibitors was 6.4 mg g^-1 dry matter. The optimal conditions derived from RSM for A. oryzae fermentation were： substrate to water ratio= 0.8 1; inoculum size=4%; duration=120 h. The minimum content of trypsin inhibitors was 1.6 mg g^-1 dry matter. Both L. brevis and A. oryzae decreased trypsin inhibitors dramatically （57.1 and 89.2% respectively）. L. brevis fermentation did not affect phytic acid （0.4%） and crude fat （5.2%） considerably, whereas A. oryzae fermentation degraded phytic acid （34.8%） and crude fat （22.0%） contents to a certain extent. Crude protein content was increased after both fermentation （6.4 and 12.9% for L. brevis and A. oryzae respectively）. Urease activity was reduced greatly （83.3 and 58.3% for L. brevis and A. oryzae respectively）. In conclusion, SSF with A. oryzae and L. brevis reduced trypsin inhibitor content and modified major macronutrients in soybean meal.

Urinary trypsin inhibitor attenuates hepatic ischemia-reperfusion injury by reducing nuclear factor-kappa B activation

BACKGROUND: Urinary trypsin inhibitor (UTI) inhibits the inflammatory response and protects against ischemia-reperfusion (I/R) injury. The inflammatory response is mediated by nuclear factor-kappa B (NF-kappa B) and its related target genes and products such as vascular endothelial cell adhesion molecule and CXC chemokines. We aimed to assess the roles of those mediators in a UTI-treated mouse model of hepatic I/R injury. METHODS: Treatment group 1 (UTI given 5 minutes prior to liver ischemia), treatment group 2 (UTI given 5 minutes after the anhepatic phase) and a control group were investigated. Blood and liver samples were obtained and compared at 1, 3, 6 and 24 hours after reperfusion. RESULTS: Attenuation of pathological hepatocellular damage was greater in the treatment groups than in the control group (P < 0.05). Compared with the control group, the UTI treatment groups showed significantly lower serum alanine aminotransferase and aspartate aminotransferase levels, decreased myeloperoxidase activity, and reduced NF-kappa B activation. Also downregulated was the expression of tumor necrosis factor-alpha, cytokine-induced neutrophil chemoattractant, and macrophage inflammatory protein-2 at the mRNA level. P-selectin protein and intercellular adhesion molecule-1 protein expression were also downregulated. In addition, the treatment group I showed a better protective effect against I/R injury than the treatment group 2. CONCLUSIONS: UTI reduces NF-kappa B activation and downregulates the expression of its related mediators, followed by the inhibition of neutrophil aggregation and infiltration in hepatic I/R injury. The protective role of UTI is more effective in prevention than in treatment.

Pancreatic secretory trypsin inhibitor:More than a trypsin inhibitor

Kazal-type serine protease inhibitor is one of the most important and widely distributed protease inhibitor families. Pancreatic secretory trypsin inhibitor (PSTI), also known as serine protease inhibitor Kazal type I(SPINK1), binds rapidly to trypsin, inhibits its activity and is likely to protect the pancreas from prematurely activated trypsinogen. Therefore, it is an important factor in the onset of pancreatitis. Recent studies found that PSTI/SPINK1 is also involved in self-regulation of acinar cell phagocytosis, proliferation and growth of a variety of cell lines. In addition, it takes part in the response to inflammatory factor or injury and is highly related to adult type II citrullinemia.

Purification, characterization and evaluation of insecticidal activity of trypsin inhibitor from Albizia lebbeck seeds

A Bowman-Birk inhibitor with activity against gut proteases of Helicoverpa armigera was extracted in 0.I M sodium phosphate buffer from defatted seed flour of Albizia lebbeck. It was purified to 29.62 folds with 51.43% recovery using ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-100 column and ion ex- change chromatography on DEAE-Sephadex As0. The purified protein had a molecular weight of 12,303 daltons as determined by SDS-PAGE. It was found to be heat stable up to 60~C and had two pH optima of 7.5 and 9.0. The inhibitor exhibited non-competitive pattern of inhibition with a low Ki value of 0.2 ~tM. The inhibitoi- was found to be susceptible to varying concentrations of reducing agents like DTT and 2- mercaptoethanol, thereby indicating the role of disulphide bridges in maintaining its three dimensional structure and stability. The purified inhibitor caused mortality and suppressed larval growth ofPieris brassi- cae larvae. It was also found to be effective against gut trypsin extracted from Spodoptera littoralis. The sequence of the genes encoding for such inhibitors can be determined and the genes expressing protease inhibitors can be used in vegetable crops to confer resistance against insect pests and other plant pathogens.

Purification and Trypsin Inhibitor Activity of a Sporamin B from Sweet Potato (Ipomoea batatas Lam. 55-2)

Sporamin is a soluble protein in sweet potato, and falls into two distinct homology groups, subfamilies A and B. In this research, a sporamin B was purified and its amino acid sequences, trypsin inhibitor activity （Ti activity） were analyzed. This sporamin B was isolated from sweet potato tubers [Ipomoea batatas （L.） Lam cv. 55-2] through extraction of the water-soluble fraction, dialysis, ultrafiltration and ion-exchange chromatography. Homology determined by polyacrylamide gel electrophoresis showed that mainly one bond appeared in gel after being reduced by SDS （sodium dodecyl sulfate）, or by SDS and 2-mercaptoethanol, or in native situation. By comparing the data of the polypeptide mass Matrix-assisted laser desorption/ionization time-of-flight （MALDI-TOF） mass spectrometry with those of the mass of the theoretical amino acid sequences from NCBI protein database, it was revealed that it was Q40091｜Q40091_IPOBA, sweet potato sporamin B - Ipomoea Batatas （sweet potato） （Batate）. The sequence coverage was 70.6%. N-terminal sequence was SETPV （Ser-Glu-Thr-Pro-Val）. There is a linear relationship between trypsin inhibitor activity （Ti activity） and amounts of this sporamin B （3-18 μg mL-1）. The equation of linear regression was y = 2.5809x ＋ 17.049 （r2 = 0.9966）. There was a curvilinear relationship between Ti activity and amounts of this sporamin B （21-150 μg mL-1）. The equation of curvilinear regression is y = 14.417ln（x） ＋ 23.26 （r2 = 0.9924）. The concentration of sporamin B with Ti activity after heating at 40°C may induce part denature of this sporamin B, and there was no statistic difference after heating at 40, 50, 60°C for 20 min. Heat treatment at more than 90°C leads to a dramatic decrease of trypsin inhibitor efficiency. The results suggested that Q40091｜Q40091_IPOBA was the major sporamin B in sweet potato tubers [Ipomoea Batatas （L.） Lam cv. 55-2], which had strong Ti activity, and was stable to both thermal and DTT （DL-dithiothreitol） relatively.

Silica-supported Macroporous Chitosan Bead for Affinity Purification of Trypsin Inhibitor

Macroporous cross-linking chitosan layer coated on silica gel （CTS-SiO2） was prepared by phase inversion and polyethylene glycol （PEG）molecular imprinting methods. Formation of macroporous surtace was investigated by scanning electron microscopy （SEM） and BET analysis.The prepared bead was activated by reacting with 1,2-ethylene digiycidyl ether for introducing epoxy groups, and trypsin could be efficiently immobilized on the bead as a biospecific ligand.The bead bearing trypsin was employed to purify trypsin inhibitor （TIs） from egg white as affinity adsorbent.

A Novel Trypsin Inhibitor-Like Cysteine-Rich Peptide from the Frog Lepidobatrachus laevis Containing ProteinaseInhibiting Activity

Various bio-active substances in amphibian skins play important roles in survival of the amphibians.Many protease inhibitor peptides have been identified from amphibian skins,which are supposed to negatively modulate the activity of proteases to avoid premature degradation or release of skin peptides,or to inhibit extracellular proteases produced by invading bacteria.However,there is no information on the proteinase inhibitors from the frog Lepidobatrachus laevis which is unique in South America.In this work,a cDNA encoding a novel trypsin inhibitor-like(TIL)cysteine-rich peptide was identified from the skin cDNA library of L.laevis.The 240-bp coding region encodes an 80-amino acid residue precursor protein containing 10 half-cysteines.By sequence comparison and signal peptide prediction,the precursor was predicted to release a 55-amino acid mature peptide with amino acid sequence,IRCPKDKIYKFCGSPCPPSCKDLTPNCIAVCKKGCFCRDGTVDNNHGKCVKKENC.The mature peptide was named LL-TIL.LL-TIL shares significant domain similarity with the peptides from the TIL supper family.Antimicrobial and trypsin-inhibitory abilities of recombinant LL-TIL were tested.Recombinant LL-TIL showed no antimicrobial activity,while it had trypsin-inhibiting activity with aKi of 16.5178 lM.These results suggested there was TIL peptide with proteinase-inhibiting activity in the skin of frog L.laevis.To the best of our knowledge,this is the first report of TIL peptide from frog skin.

CRYSTAL STRUCTURE OF THE COMPLEX OF MUNG BEAN TRYPSIN INHIBITOR LYSINE ACTIVE FRAGMENT WITH BOVINE TRYPSIN AT 1.8 A RESOLUTION

The structure of the complex of mung bean trypsin inhibitor lysine active fragment with bovine trypsin has been determined at a resolution of 1.8 A by A-ray crystallographic analysis and the complex model refined by restrained least-squares minimization with the data between 10 and 1.8 resolution.The current conventional R factor is 17.3%,and the model con- tains 1648 protein atoms,219 inhibitor atoms and 126 water molecules.The most prominent feature of the inhibitor fragment is that it does not contain any alpha-helices.Most of the chain fold in an irregular fashion.The seven residues of the binding segment of the inhibitor lysine active frag- ment are in specific contact with bovine trypsin.The binding interaction and geometry around the reactive site are similar to that observed in other studies of trypsin-inhibitor complexes.

Optima of Trypsin-Catalyzed Hydrolysis and Its Inhibition Determined by SDS-PAGE

SDS-PAGE was applied to determine trypsin activity and inhibition. After the hydrolysis by trypsin to substrate bovine serum albulnin (BSA) under different temperatures and pH, the hydrolysis degree of BSA was conducted using SDS-PAGE. From the quantitative analysis to the electrophoresis bands of BSA and its hydrolysis products in SDS-PAGE pattern, the change of trypsin activity was determined, and then the optimum temperature at 40°C and the optimum pH at pH 8.5 - 8.7 for trypsin activity were obtained. All the target bonds in BSA molecule could be hydrolyzed at the same time by trypsin. The inhibition was due to the binding of inhibitor to trypsin, which made it impossible for trypsin to touch the substrate protein. SDS-PAGE was demonstrated to be also an effect method for assaying the characteristics of trypsin activity and its inhibition.

Increasing Accumulation Level of Foreign Protein in Transgenic Plants Through Protein Targeting

Targeting of the synthesized polypeptide in the cells is an important research field in modern cell biology. Cowpea trypsin inhibitor (cpti) gene has been modified and a fusion protein gene (sck) was produced by fusing a signal peptide sequence at cpti 5' end and an endoplasm reticulum (ER) retention signal peptide at cpti3' end respectively. The signal peptide can direct the newly synthesized polypeptide into ER, while ER retention signal can make the protein retained in the ER and its derivative protein body. ELISA test indicated that the accumulation level of foreign CpTI protein in sck transgenic tobacco (Nicotiana tabacum L.) was two times higher than cpti transgenic tobaccos and some individuals were four times higher. At the same time, sck transgenic tobacco has a high resistance to Lepidoptera pest due to the increased accumulation level of foreign CpTI protein. The strategy of foreign protein targeting can be used to increase the accumulation level of foreign protein in transgenic plants and can be widely applied to other related research field in plant genetic engineering.

An HPLC method for the assay of trypsin inhibitors and its application to the study of Momordica cochinchinensis extract

A reliable and validated HPLC method was established for the assay of trypsin inhibitors（TI）and it was used in the investigation of the active TI components inMomordica cochinchinensis（Cucurbitaceae family）.The underlying principle of the assay is the measurement of the decrease in trypsin activity due to the presence of TI in analyzed samples,which was achieved by using HPLC separation and quantification of p-nitroanilide that was generated by tryptic hydrolysis of N-α-benzoyl-DL-arginine -4-nitroanilide.The results showed that the HPLC method had higher selectivity than conventional spectrophotometric assay.

Test of Insect-Resistance of Transgenic Poplar with CpTI Gene

Both non-transgenic hybrid triploid poplars [ (Populus tomentosa×P.bolleana)×P.tomentosa ] and transgenic ones expressing cowpea trypsin inhibitor were cut at the base of the stem to produce auxoblasts, and used as source of leaves for insect feeding trials performed on 3 major insect species of poplar, the forest tent caterpillar ( Malacosoma disstria L.), gypsy moth ( Lymantria dispar L.) and willow moth ( Stilpnotia candida Staudinger). The height and basal diameter of trees were measured by the end of that year (2000). The results indicated that the growth elements of transgenic poplars were not interfered by the incorporation of the CpTI gene. Intriguingly, the height and basal diameter of the clone TG04 were much greater than that of the control. The transgenic foliage consumed by insects induced the increase of larval mortality, and decrease of larval wet weight gain, faecal output, pupal weight and egg deposition. Among them 3 transgenic clones, TG04, TG07 and TG71 received special attention for their outstanding insect resistance compared with other transgenic clones, which showed that the CpTI gene in them was expressed more actively and stably than in others.

Elevated plasma cryofibrinogen in patients with active inflammatory bowel disease is morbigenous

AIM： To investigate the role of cryofibrinogen （CF） in active inflammatory bowel disease （IBD）. METHODS： CF was assayed in 284 subjects： 61 with active and 63 with inactive ulcerative colitis （UC）, 45 who had proctocolectomy, 35 with active and 20 with inactive Crohn＇s disease （CD）, 40 with other diseases and 20 healthy controls. Trypsin inhibitor （TI） and TI antibody （TI-Ab） were measured in plasma and CF complex by ELISA. RESULTS： CF in active UC was strikingly high compared with all other groups （x^2〈0.001）. Similarly, CF was significantly higher in active CD than in inactive CD or in controls （x^2〈0.01）. In UC, high CF and TI-Ab were associated with the need for operations. Further, high CF, CF/fibrinogen ratio, low TI and high TI-Ab in plasma were associated with disease activity or refractoriness to medication. Elevated CF was not associated with acute reactants like C-reactive protein and white blood cell counts except for erythrocyte sedimentation rate, suggesting that elevated CF was not a consequence of acute inflammation. CONCLUSION： Elevated CF in active IBD appears to be morbigenous. CF promotes IBD via two main mechanisms, quenching of TI （an anti-inflammatory substance） and impairing microvascular perfusion by forming protein aggregates. CF may also serve as a biomarker of chronic IBD. Additional studies are warranted to fully evaluate the role of CF in IBD and the outcome should contribute to a better understanding of the pathogenesis of IBD.

Identification of CpTI Gene Integration for 2-year-old Transgenic Poplars at DNA Level

The putative transgenic hybrid triploid poplars [(P. tomentosa P. bolleana) P. tomentosa] with CpTI gene have been outplanted in test field for 2 years. Although the authors previous studies have proved that they are highly resistant to 3 species of poplar-threatening insect pests and contain high content of CpTI protein in foliage, incorporation status of foreign CpTI gene in poplar genome is uncertain. In this present study, the incorporation of foreign CpTI gene in genome of 5 transgenic poplars was confirmed by PCR and Southern blotting analysis. DNA amplification showed that there were clear DNA bands of about 450bp specific to CpTI gene in transgenic lanes, while no corresponding band in non-transgenic lane was observed. Correspondingly, clear DNA hybridization signals and no signal were exhibited on film for DNA Southern blotting analysis in transgenic lanes and non-transgenic lane, respectively, which further confirmed the stable integration of foreign CpTI gene in genome of 2-year-old transgenic poplar.

Effect of germination on the nutritional quality of Pearl millet

Changes in proximate composition, trypsin inhibitor activity, phytic acid, tannins, in vitro protein digestibility and amino acids content of Pearl millet were investigated after germination for 5 days. Germination significantly increased protein content of pearl millet, with a parallel decrease in lipid and carbohydrates. Trypsin inhibitor activity and the phytic acid content showed significant decrease whereas tannin content increased after 5 days germination. In vitro protein digestibility （IVPD） was significantly decreased with germination, suggesting that tannins may be responsible for enzymes inhibition. Amino acid analysis revealed significant increase in essential amino acids and none essential amino acids.

Vegetative Storage Protein with Trypsin Inhibitor Activity Occurs in Sapindus mukorassi,a Sapindaceae Deciduous Tree

A vegetative storage protein （VSP） with trypsin inhibitor activity in a deciduous tree, Sapindus mukorassi, was characterized by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western-blot, immuno-histochemical localization, light- and electro-microscopy, together with analysis of proteinase inhibitor activity of the purified VSP in vitro. There were two proteins with molecular masses of about 23 and 27 kDa in a relatively high content in the bark tissues of terminal branches of S. mukorassi in leafless periods. The proteins decreased markedly during young shoot development, indicating their role in seasonal nitrogen storage. Immuno-histochemical localization with the polyclonal antibodies raised against the 23 kDa protein demonstrated that the 23 kDa protein was the major component of protein inclusions in protein-storing cells. The protein inclusions were identified by protein-specific staining and should correspond to the electron-dense materials in different forms in the vacuoles of phloem parenchyma cells and phloem ray parenchyma cells under an electron microscope. So, the 23 kDa protein was a typical VSP in S. mukorassi. The 23 and 27 kDa proteins shared no immuno-relatedness, whereas the 23 kDa protein was immuno-related with the 22 kDa VSP in lychee and possessed trypsin inhibitor activity. The 23 kDa protein may confer dual functions： nitrogen storage and defense.

TOTAL SYNTHESIS OF Trichosanthes TRYPSIN INHIBITOR AND ITS ANALOGUE

Trichosanthes trypsin inhibitor (TTI) is a peptide consisting of 27 amino acid residues with three pairs of disulfide bonds. This paper reports the total synthesis and disulfide bond refolding of this inhibitor and its analogue. After purification, the amino acid sequence and stoichiometrical inhibitory activity against trypsin of the synthetic inhibitor were compatible with those of the natural inhibitor. The analogue of this inhibitor in which residue Met in position 6 was replaced by Ala was also synthesized. The antitrypsin activity of this synthetic analogue was also approximate to that of the natural inhibitor.

The amino acid sequence of a double-headed trypsin inhibitor from the seeds of Momordica charantia Linn.Cucurbitaceae

A double-headed trypsin inhibitor(MCI-1)was isolated and purified from the seeds of Momordica charantia Linn.Cucurbitaceae,by using the trypsin-sepharose-4B affinity chroma- tography and CM-Sephadex-C50 ion exchange chromatography.It is composed of 77 amino acid residues:Asp_8 Thr_1 Ser_4 Glu_8 Pro_2 Gly_6 Ala_4 Cys_(14) Val_2 Met_4 Ile_8 Leu_1 Phe_1 His_3 Lys_ Arg_7. The amino acid sequence of MCI-1 was determined by sequencing the cyanogen bromide,tryptic and staphylococcus aureus V8 proteolytic peptides,then aligned by overlapped sequences.The result shows that MCI-1 contains 7 pairs of disulfide bonds,its sequence showed the high homology with those of “Bowman-Birk”inhibitors.About 50% trypsin inhibitory activity still remained after MCI-1 was cleavaged with cyanogen bromide.