Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

This paper presents the experimental details which led to the elucidation of the complete primary structure of S16, a protein which belongs to the small subunit of E. coli ribosomes. Protein S16 was digested with trypsin, alpha-chymotrypsin, and the staphylococcal protease. The resulting peptides were purified on paper and their amino acid composition and sequence were determined. Automatic Edman degradation with a modified sequenator on the complete protein yielded information from the 56N-terminal residues. The combination of all these results led to the following complete amino acid sequence: Met-Val-Thr-Ile-Arg-Leu-Ala-Arg-His-Gly-Ala-Lys-Lys-Arg-Pro-Phe-Tyr-Gln-Val-Val-Val-Ala-Asp-Ser-Arg--Asn-Ala-Arg-Asn-Gly-Arg-Phe-Ile-Glu-Arg-Val-Gly-Phe-Phe-Asn-Pro-Ile-Ala-Ser-Glu-Lys-Glu-Glu-Gly-Thr-Arg-Leu-Asp-Leu-Asp-Arg-Ile-Ala-His-Trp-Val-Gly-Gln-Gly-Ala-Thr-Ile-Ser-Asp-Arg-Val-Ala-Ala-Leu-Ile-Lys-Glu-Val-Asn-Lys-Ala-Ala. The molecular weight derived from the sequence amounts to 9 162.
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PMID:The complete amino acid sequence of protein S16 from Escherichia coli. 33 10

Human granulocyte elastase (EC 3.4.21.11) differs from hog pancreatic elastase in its specificity for synthetic substrates. Although hydrolyzing peptide bonds adjacent to the carboxyl group of alanine, the granulocyte enzyme prefers valine at the cleaved bond, in contrast to the pancreatic enzyme which prefers alanine. Peptide bonds involving the carboxyl group of isoleucine can be hydrolyzed by the granulocyte enzyme but are not hydrolyzed to any significant extent extent by pancreatic elastase. This difference in specificty could explain the lower sensitivity of the granulocyte enzyme to inhibitors containing alanine analogs, such as the peptide chloromethyl ketones and elastatinal. The human granulocyte chymotrypsin-like enzyme differs from pancreatic chymotrypsin by being able to cleave substrates containing leucine in addition to those containing the aromatic amino acids.
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PMID:Sbustrate specificity of the elastase and the chymotrypsin-like enzyme of the human granulocyte. 40 49

Insoluble elastin from copper-deficient animals has an amino acid composition intermediate between mature elastin and salt-soluble elastin (a higher lysine content and correspondingly low number of cross-links relative to the normal protein) and is solubilized by successive treatment with trypsin and chymotrypsin at 4 and 37 degrees C. Small amounts of B3H4 (11 mg--2 g of elastin) reduced allysine, allysine aldol, dehydronorleucine, and dehydromerodesmosine in insoluble elastin from copper-deficient pig aorta. In contrast, desmosine and isodesmosine were reduced only when a large excess of reductant (400 mg borohydride) was included in the reaction mixture. Reduction studies indicated that lysinonorleucine and merodesmosine were present in their dehydro forms to a greater extent in copper-deficient pig elastin than in normal elastin. After reduction with borohydride approximately 35% of the reduced form of the insoluble elastin remained insoluble after digestion with trypsin and chymotrypsin. A peptide containing the aldehyde oxidation product of lysine (allysine) and demonstrating an enrichment in glutamic acid was purified from the reduced form of copper-deficient pig elastin and partially sequenced. Its sequence (Gly-Ala-Glu-allysine-(Glu)...) and amino acid composition suggest: (1) clustering of glutamic acid residues in the elastin molecule, and (2) that allysine residues are not restricted to the alanine-enriched sites described for other elastin cross-links. Insoluble elastin from copper-deficient animals promises to be a useful tool for elastin sequence studies.
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PMID:Characterization of insoluble elastin from copper-deficient pigs. Its usefulness in elastin sequence studies. 42 11

The protein moiety of squid (Watasenia scintillans) rhodopsin has been shown to have a molecular weight of 46 800 by means of amino acid analysis. This value was comparable to the value (51 000) obtained from SDS-polyacrylamide gel electrophoresis. After the squid eyes were incubated at 10 degrees C for 8 days, the rhodopsin showed a molecular weight of 39 000 on electrophoresis. The smaller molecular weight was ascertained by amino acid analysis of the rhodopsin; and may result from autolysis by the lysosomal enzyme. The rhodopsin in rhabdomeric membranes and in detergent solution was treated with chymotrypsin, papain or subtilisin. These enzymes first produced the 39 000 dalton rhodopsin and then cleaved this into the 25 000 and 14 000 dalton peptides without bleaching. The rhodopsin was attacked by proteases and readily lost an approx. 12 000 dalton peptide portion. This portion included the COOH-terminal and was rich in glutamic acid, proline, glycine, alanine and tyrosine residues.
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PMID:Molecular weight and structural studies on cephalopod rhodopsin. 46 26

We present in this paper the sequence of the heme-binding domain of chicken sulfite oxidase which can be obtained by chymotryptic digestion of the native enzyme. The results of an automatic degradation have been reported previously. In the present work peptides were obtained from the heme-binding domain by digestion with trypsin, chymotrypsin and Staphylococcus aureus V8 protease; they were manually sequenced by the dansyl/Edman procedure. The evidence thus obtained is sufficient to completely establish the order of the 97 residues. In addition, two rounds of Edman degradation on sulfite oxidase itself allowed us to identify the same two residues, H-Ala-Pro, present at the N-terminus of the heme-binding domain; this result suggests that the latter constitutes the amino-terminal end of the sulfite oxidase peptide chain. The data presented here confirm the strong similarity between sulfite oxidase and microsomal cytochrome b5 already suggested by our first results. A sequence alignment is proposed for the two proteins. Inspection of the calf liver cytochrome b5 three-dimensional model together with the alignment suggests a similar overall structure for sulfite oxidase core with a limited number of backbone modifications. Our results point to a common evolutionary origin for sulfite oxidase core and microsomal cytochrome b5.
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PMID:Amino acid sequence of the 'b5-like' heme-binding domain from chicken sulfite oxidase. 51 Feb 90

Alanine-neochymotrypsinogen was prepared by incubating 20 parts bovine pancreas chymotrypsinogen A with one part alpha-chymotrypsin in a solution containing 1 M (NH4)2SO4, 0.1 M sodium acetate, 0.05 M Tris buffer (pH 8.0) and 0.5 mg/ml soybean trypsin inhibitor. Optimal yields of NH2-terminal alanine were obtained after 60 h incubation at 4 degrees C. Ala-neochymotrypsinogen was isolated from the reaction mixture by affinity chromatography and ion-exchange chromatography on carboxymethyl-cellulose. As expected, the purified preparation was enzymatically inactive and, compared to chymotrypsinogen, had one additional NH2-terminal group identified as alanine. Ala-neochymotrypsinogen was activated by incubating with trypsin at a zymogen : trypsin ratio of 30 : 1 in 0.1 M phosphate buffer, pH 7.6 at 4 degrees C for 1 h. The fully active, stable species was identified as alpha-chymotrypsin.
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PMID:On the activation of bovine chymotrypsinogen A. Preparation of alanine-neochymotrypsinogen and its activation to alpha-chymotrypsin. 56 99

Soybean inhibitor C-II, which inhibits trypsin, alpha-chymotrypsin, and elastase, was reduced and S-carboxymethylated, and digested with trypsin. The amino acid sequences of the resulting tryptic peptides were determined by conventional methods, establishing the complete 76-amino acid sequence of the inhibitor. Inhibitor C-II was found to be homologous with soybean (Glycine max) Bowman-Birk inhibitor and more closely related to an inhibitor from garden beans (Phaseolus vulgaris). The homology with these inhibitors and the limited proteolysis of C-II indicated the reactive sites of C-II for elastase and trypsin to be alanine-22 and arginine-49, respectively. Arginine-49 was also identified as a reactive site for alpha-chymotrypsin. It was found that only a few replacements of one or two amino acid residues around the reactive sites resulted in considerable alteration of the inhibitory specificity.
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PMID:Studies on soybean trypsin inhibitors. XI. Complete amino acid sequence of a soybean trypsin-chymotrypsin-elastase inhibitor, C-II. 59 41

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

The acetylpeptides derived from S-carboxymethylovalbumin by cyanogen bromide and chymotrypsin have been isolated and shown by enzyme digestion and the dansyl-Edman method to fit the sequence acetyl-Gly-Ser-Ile-Gly-Ala-Ala-Ser-Met-Glu-Phe. This corrects the order of the third and fourth residues in the five-residue sequence given by Narita and Ishii [J. Biochem. (Tokyo), 1962, 52, 367--73]. The overlap of the C-terminal sequence of this extended sequence with the six-residue N-terminal sequence surrounding a half-cystine residue in ovalbumin gives the N-terminal sequence for ovalbumin as acetyl-Gly-Ser-Ile-Gly-Ala-Ala-Ser-Met-Glu-Phe-Cys-Phe-Asp-Val-Phe-Lys with residue 11 a cysteine residue.
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PMID:A correction and extension of the acetylated amino terminal sequence of ovalbumin. 75 25

Kinetic constants are reported for alpha-chymotrypsin-, Streptomyces griseus protease 3 (SGP3)-, and elastase-catalyzed hydrolysis of a number of peptides. SGP3, like alpha-chymotrypsine, hydrolyzes most readily amide bonds whose immediate acyl group (P1) is a large, hydrophobic, amino acid residue. SGP3, however, has a broader specificity for P1 residues than does alpha-chymotrypsin, primarily because the most important interactions between SGP3 and residue P1 of the substrate involve the Cbeta and Cgamma groups of the P1 side chain. For substrates of all three proteases, the amino acid residue contributing the amino group of the scissile bond (P1') is less important than P1 in determining kcat/Km for the hydrolysis reaction. Each enzyme interacts favorably with a hydrophobic P1' side chain. A substate with a large P1' side chain is bound more strongly, but is hydrolyzed less rapidly, than that with P1' Ala. The observation that strong binding of P1' is not necessarily conducive to rapid hydrolysis is consistent with the idea that parts of P1' must undergo a considerable displacement during substrate hydrolysis.
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PMID:The active centers of Streptomyces griseus protease 3, alpha-chymotrypsin, and elastase: enzyme-substrate interactions close to the scissile bond. 81 25


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