Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two proteinase inhibitors, designated as inhibitors I and II, were purified from adzuki beans (Phaseolus angularis) by chromatographies on DEAE- and CM-cellulose, and gel filtration on a Sephadex G-100 column. Each inhibitor shows unique inhibitory activities. Inhibitor I was a powerful inhibitor of trypsin [EC 3.4.21.4], but essentially not of chymotrypsin ]EC 3.4.21.1]. On the other hand, inhibitor II inhibited chymotrypsin more strongly than trypsin. The molecular weights estimated from the enzyme inhibition were 3,750 and 9,700 for inhibitors I and II, respectively, assuming that the inhibitions were stoichiometric and in 1 : 1 molar ratio. The amino acid compositions of both inhibitors closely resemble those of low molecular weight inhibitors of other leguminous seeds: they contain large amounts of half-cystine, aspartic acid and serine, and little or no hydrophobic and aromatic amino acids. Inhibitor I lacks both tyrosine and tryptophan residues. The molecular weights were calculated to be 7,894 and 8,620 for inhibitors I and II, respectively. The reliability of these molecular weights was confirmed by the sedimentation equilibrium and 6 M guanidine gel filtration methods. On comparison with the values obtained from enzyme inhibition, it was concluded that inhibitor I and two trypsin inhibitory sites on the molecule, whereas inhibitor II had one chymotrypsin and one trypsin inhibitory sites on the molecule.
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PMID:Purification and characterization of proteinase inhibitors from adzuki beans (Phaseolus angularis). 0 91

A trypsin inhibitor was isolated from beans of Phaseolus vulgaris, cultivar. Kintoki, and the specific activity increased 200 times as high as that of the crude extract. It was homogeneous on several electrophoreses and the molecular weight was about 13,000. The amino acid composition was characterized by high ratios of cystine, aspartic acid, and serine. It inhibited trypsin in a molar ratio of 1 : 1 and alpha-chymotrypsin in a molar ratio of 2 : 1. It, however, inhibited neither pepsin nor pronase. It was relatively stable to heat treatment in the acidic medium, but not in the alkaline medium. Neither pepsin nor pronase destroyed the inhibitory function.
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PMID:The isolation and characterization of a trypsin inhibitor from Kintoki bean (Phaseolus vulgaris). 2 95

The amino acid sequence of staphylococcal protease has been determined by analysis of tryptic peptides obtained from cyanogen bromide fragments. Selected peptides obtained from digests with staphylococcal protease, thermolysin, and chymotrypsin provided the information necessary to align the tryptic peptides and the cyanogen bromide fragments. The protease is a single polypeptide chain of some 250 amino acids and is devoid of sulfhydryl groups. The COOH-terminal tryptic peptide of of the protease molecule contains some 43 residues, most of which are aspartic acids, asparagines, and prolines. The amino acid sequence of this peptide was not determined. The primary structure near the active serine residue indicates that staphylococcal protease is related to the pancreatic serine proteases. However, it has little or no additional sequence homologies with these enzymes except for the regions near histidine-50 and aspartic acid - 91. These regions have striking similarities with the corresponding regions of protease B and the trypsin-like enzyme of Streptomyces griseus.
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PMID:The primary structure of staphylococcal protease. 9 22

The use of a linear free-energy relationship shows that both histidine residues of alpha-chymotrypsin and chymotrypsinogen are super-reactive toward 1-fluoro-2,4-dinitrobenzene. The binding of indole to the specificity site of alpha-chymotrypsin causes both histidine residues to become less reactive. On the basis of these results and those from X-ray-crystallographic studies, the following conclusions are made. (1) The super-reactivity of the catalytic-site histidine-57 is due to charge transfer from aspartic acid-102 by means of hydrogen bonding. (2) The aspartic acid-102-histidine-57-serine-195 'charge-relay' system is not complete in the zymogen or native enzyme and only on binding of a suitable substrate or ligand to the specificity site of the enzyme is the charge transfer to serine-195 completed. (3) The lack of substantial enzymic activity in the zymogen is due to the absence of a completed specificity site, and therefore it cannot bind suitable substrates or ligands to induce completion of the charge-relay system.
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PMID:Properties of the histidine residues of indole-chymotrypsin. Implications for the activation process and catalytic mechanism. 24 27

A trypsin inhibitor isolated from a potato acetone powder has been purified by affinity chromatography. This protein inhibits trypsin mole per mole. To a lesser extent it combines also with chymotrypsin and elastase. For trypsin, K1 = 8 X 10(-7) M. The inhibitor has a single polypeptide chain of 207 amino acid residues. It contains no sugar or free sulfhydryl groups. Its extinction coefficient E2801% = 10.3 and its isoelectric point is 6.9. Its molecular weight is of the order of 21 000-22000, as determined by sedimentation equilbrium, by inhibition experiment or from its amino acid composition. These same techniques, taken together with the single band observed at different pH on polyacrylamide gel electrophoresis, indicate that the protein purified is monodisperse. However, the finding of two N-terminal amino acid residues, leucine and aspartic acid, and the different stoichometry observed during the interaction of the inhibitor, either with trypsin or with chymotrypsin and elastase, raises the possibility that our preparation is contaminated by a polyvalent inhibitor not detectable by physiochemical methods.
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PMID:Purification and characterization of a trypsin inhibitor from Solanum tuberosum. 24 76

The trypsin inhibitors from winged bean seed were isolated by affinity chromatography on trypsin-Sepharose 4B and the components fractionated by chromatography on SP-Sephadex C-25 and Sephadex G-100. The major components, inhibitors 2 and 3 were found to be homogeneous proteins with molecular weights of about 20,000. The inhibitors stoichiometrically inhibited bovine trypsin in the molar ratio of 1 : 1 whereas the inhibition of bovine alpha-chymotrypsin was weak and non-stoichiometric. Amino acid analysis indicated that both the inhibitors contain four cysteine residues and are rich in aspartic acid, glutamic acid, glycine, valine and leucine; however, inhibitor 3 lacks histidine and methionine while inhibitor 2 contains one histidine and three methionines. A minor trypsin inhibitor fraction was also isolated which contained at least three proteins with a molecular weight of about 10,000 and a high content of half-cystine.
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PMID:Isolation and characterization of the trypsin inhibitors from winged bean seed (Psophocarpus tetragonolobus (L) Dc.). 45 47

The complete amino acid sequence of a basic non-histone protein, H6, isolated from the chromatin of rainbow trout (Salmo gairdnerii) testis cells, has been determined. Protein H6, first described by D. T. Wigle and G. H. Dixon [J. Biol. Chem. 246, 5636--5644 (1971)] was extracted with 5% trichloracetic acid and purified by ion-exchange chromatography on carboxymethyl-cellulose (CM-52). Sequence analysis was performed by automatic Edman degradation of the amino terminus of the intact protein and a series of large fragments derived by cleavage with chymotrypsin, staphylococcal protease and with mild acid to cleave at aspartic acid residues. Protein H6 possesses 69 residues and shows considerable similarities to the 89-residue calf thymus HMG-17 protein previously sequenced [Walker, J. M., Hastings, J. R. B. & Johns, E. W. (1977) Eur. J. Biochem. 76, 461--468]. B. Levy W. and G. H. Dixon [Proc. Natl Acad. Sci. U.S.A. 74, 2810--2814 (1977)] have shown that H6 is selectively solubilized when trout testis nuclei (or chromatin) are digested with DNase I under conditions which preferentially hydrolyze that portion of DNA enriched in transcribed sequences [Levy, W. B. & Dixon, G. H. (1977) Nucleic Acids Res. 4, 883--898]. Recently H6 has been located as a stoichiometric component of a distinct subset of trout testis nucleosomes that are complexed with a core nucleosome comprising 140 base pairs of DNA and the inner histones H2A, H2B, H3 and H4 [Levy, W. B., Connor, W. & Dixon, G. H. (1979) J. Biol. Chem., in the press].
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PMID:The complete amino-acid sequence of a trout-testis non-histone protein, H6, localized in a subset of nucleosomes and its similarity to calf-thymus non-histone proteins HMG-14 and HMG-17. 45 49

An enzyme that catalyzes the conversion of 2-amino-6-(5'-triphosphoribosyl)amino-5- or 6-formamido-6-hydroxypyrimidine, but not of guanosine triphosphate, to quinonoid 6-(D-erythro-1'-2'-3'-trihydroxypropyl)dihydropterin triphosphate and formic acid has been purified to homogeneity from some mammalian brain and liver. The enzyme of a single strand is a basic protein of 9177 daltons consisting of 68 amino acid residues--except the enzyme from rat brain, which has one additional aspartic acid as residue 7. The enzyme possesses three free SH groups and, in its most active form, 1 mol of phosphate per mole of enzyme. Peptides isolated after hydrolysis with trypsin, chymotrypsin, or weak acid were separated by thin-layer chromatography and sequenced manually by Edman degradation. The complete sequence of the molecule was established as follows: (formula: see text)
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PMID:Biopterin. VI. Purification and primary amino acid sequence of mammalian D-erythro-7,8-dihydroneopterin triphosphate synthetase. 49 48

A trypsin inhibitor was isolated and purified from the bran of rice, Oryza sativa, by extraction with 1% sodium chloride, heat treatment, ammonium sulfate precipitation, ion-exchange chromatography on a CM-Sephadex C-25 and gel filtration on a Sephadex G-75. The final preparation was homogeneous by electrophoretic analysis. Rice bran trypsin inhibitor (RBTI) had a molecular weight of about 14,500 and an isoelectric point of 8.07. The amino acids, acid composition was characterized by high contents of basic amino acids, aspartic acid, glutamic acid, proline and cystine. BRTI inhibited bovine trypsin at an inhibitor-enzyme molar ratio of 1:1.6. It displayed, however, nobility to inhibit alpha-chymotrypsin, pepsin, papain and subtilisin BPN'.
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PMID:Purification and characterization of a trypsin inhibitor from rice bran. 50 53

Casein was modified by use of a series of active N-hydroxy-succinimide esters of amino acids in order to study the effects of new covalently linked hydrophobic or hydrophilic groups on its physical and nutritional properties. Tryptophan was used to determine the best conditions for the chemical reaction and to study the stability of the newly formed amide linkage (isopeptide bond). Casein was also modified with glycine, alanine, methionine, N-acetyl-methionine and aspartic acid. In vitro hydrolysis studies using bovine chymotrypsin, pancreatine and rat bile-pancreatic juice indicated that digestibility of the modified casein derivatives was lower than that of the untreated protein. Since solubility was not significantly changed (except for tryptophyl-casein), the decreased in vitro digestibility is probably due to other factors such as steric hindrance as well as decrease in lysine residues available to trypsin in pancreatin and rat pancreatic juice. Plasma amino acid patterns for rats fed a 10% protein diet of highly modified glycyl-casein or methionyl-casein suggest that the epsilon-aminolysyl derivatives are readily hydrolyzed in vivo. This was confirmed by the growth response of rats fed the following isonitrogenous diets (protein source listed only): casein, casein + free methionine, methionyl-casein, casein + free N-acetyl-methionine, N-acety-methionyl-casein. Covalently attached methionine appeared to be as readily available as the free amino acid; bound N-acetyl-methionine was also available but to a slightly lower extent. Although this study is preliminary, the covalent attachment of amino acids to proteins appears to be a promising method for improving the biological value of food proteins.
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PMID:A method for improving the nutritional value of food proteins: covalent attachment of amino acids. 72 27


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