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)

1. The reactivities of phenylglyoxal (PGO), glyoxal (GO), and/or methylglyoxal (MGO) with several proteins, including ribonuclease A [EC 3.1.4.22] and its derivatives, alpha-chymotrypsin [EC 3.4.21.1], trypsin [EC 3.4.21.4], lysozyme [EC 3.2.1.17], pepsin [EC 3.4.23.1], rennin [EC 3.4.23.4], thermolysin, and insulin and its B chain, have been examined. From analyses of the reaction products, PGO was shown to be the most specific for arginine residues. GO and MGO also reacted rapidly with arginine residues, but they also reacted with lysine residues to a significant extent. A side reaction with N-terminal alpha-amino groups was observed with each of these reagents. 2. Two arginine residues out of four in ribonuclease A, two out of three in alpha-chymotrypsin, one out of two in trypsin, one out of two in pepsin, and one out of five in rennin appeared to react with PGO fairly rapidly, indicating a difference in the relative accessibility of these residues by the reagent. Extensive modification of the arginine residues by PGO occurred with RCM-derivatives of ribonuclease A and insulin B chain. The N-terminal isoleucine residues of alpha-chymotrypsin and trypsin appeared to be unreactive with PGO because of salt bridge formation with an aspartyl residue. The activity of alpha-chymotrypsin toward N-benzoyl-L-tyrosine ethyl ester and the lytic activity of lysozyme were lost rapidly on treatment with PGO, as in the case of ribonuclease A. Pepsin and rennin were only partially inactivated by reaction with PGO.
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PMID:Further studies on the reactions of phenylglyoxal and related reagents with proteins. 32 41

Two new human cell lines, RCM-1 and CoCM-1, have been established from primary colorectal adenocarcinomas. Both cell lines were unique in that the cultures secreted trypsin inhibitors in vitro. The activities of these inhibitors were accumulated in serum-free media of both cell lines over a period of several days. Two inhibitors (PI-1 and PI-2) were isolated from serum-free conditioned medium in which RCM-1 was grown by anion-exchange and gel filtration high-performance liquid chromatography. PI-1 inhibited trypsin and chymotrypsin strongly, and pancreatic elastase weakly. Its molecular weight was about 57 kilodaltons (Kd) as determined by gel filtration chromatography. It cross-reacted with the antiserum elicited against human alpha 1-antitrypsin in double immunodiffusion. PI-1 corresponding to alpha 1-antitrypsin was also demonstrated immunohistochemically in both cell lines. PI-2 inhibited trypsin strongly, and chymotrypsin, kallikrein and plasmin weakly. It had higher molecular weight (200-300 Kd) than that of PI-1, and did not cross-react with antisera against human alpha 1-antitrypsin, alpha 2-macroglobulin, alpha 1-antichymotrypsin, alpha 2-plasmin inhibitor, inter-alpha-trypsin inhibitor and urinary trypsin inhibitor. RCM-1 and CoCM-1 are the first colorectal adenocarcinoma cell lines that secrete functionally active trypsin inhibitors, including alpha 1-antitrypsin in vitro, and are useful for the study of tumor-cell derived proteinase inhibitors.
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PMID:New human colorectal carcinoma cell lines that secrete proteinase inhibitors in vitro. 257 Apr 82

1. RNase Ms, a base non-specific RNase from Aspergillus saitoi was reduced and carboxymethylated (RCM-RNase Ms). RCM-RNase Ms was hydrolyzed with trypsin, and the trypsin digests were then treated with chymotrypsin. Trypsin digests were also treated with Staphylococcus protease and with chymotrypsin, separately. 2. By the analyses of the amino acid sequences of the peptides formed, the alignment of these peptides in RCM-RNase Ms was determined. 3. From the digest of heat-denatured RNase Ms with Bacillus subtilis protease, two peptides containing disulfide bridges were isolated. From the analysis of these two peptides, the locations of the bridges were determined. 4. The amino acid sequence of RNase Ms was compared with those of RNase T1 (Asp. oryzae, guanine specific), RNase U1 (Ustilago sphaerogena, guanine specific) and RNase U2 (Ustilago sphaerogena, purine specific). There are very similar sequences between these for RNases irrespective of their differences in base specificity. These were, in RNase Ms, tripeptide sequence containing His39 (Tyr-Pro-His), the tetrapeptide containing Glu57 (Glu-Tyr-Pro-Ile), the hexapeptide containing Arg76 (Asp-Arg-Val-Ile-Phe-Asp) and the hexapeptide containing His 91 (Ile-Thr-His-Thr-Gly-Ala). The other sequences common for all four RNases are Tyr67, Phe100, and Cys103 in RNase Ms. Since among these peptides His39, Glu57, His91, and Arg76 in RNase Ms corresponded to His40, Glu58, His92, and Arg77 in RNase T1 which are known to be involved in the active site of RNase T1, the possible role of these amino acids in the active site of RNase Ms is discussed. 5. The sequence similarity of RNase Ms to that of RNase T1 was about 60% and to those of RNase U1 and RNase U2 was about 30%. 6. The details of the experimental evidence used to elucidate the amino acid sequence of RNase Ms are described in the supplemental miniprint.
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PMID:Primary structure of a minor ribonuclease from Aspergillus saitoi. 709 2

Bungarus multicinctus phospholipase A was reduced and carboxymethylated. The RCM-enzyme was digested with TPCK-trypsin or cleaved with cyanogen bromide followed by chymotrypsin digestion. The resulting peptide mixtures were fractionated by gel filtration on Sephadex G-50 and G-25 columns or by DEAE-cellulose (DE-32) column chromatography. Further purification of the peptide mixtures was performed by paper electrophoresis at pH 3.5 or 6.5 or by paper chromatography. The sequences of isolated peptides were determined by the manual Edman or dansyl-Edman method. From the sequences of these peptides the whole enzyme sequence (total 118 residues) was deduced. The complete sequence of the enzyme is similar to those of phospholipases A2 from other snake venoms and mammalian pancreas. Further, a 58% sequence homology was found between the present phospholipase A and the A chain of beta 1-bungarotoxin, a presynaptic neurotoxin having weak phospholipase A activity, contained in the same venom.
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PMID:Amino acid sequence of phospholipase A from Bungarus multicinctus venom. 721 37

The boar transition protein 3 (TP3) was extracted with acid from the isolated late spermatid nuclei or directly from the testes, fractionated with trichloroacetic acid, and reduced and carboxymethylated (RCM-). RCM-TP3 from the nuclei was purified by HPLCs on Nucleosil 300 7C18 and Hitachi #3057, and that from the testes, by ion-exchange chromatography on CM-Sephadex C-25 and HPLCs on Nucleosil 300 7C18 and Chemcosorb 7C8. The two TP3 preparations were identical in acid-urea- and SDS-gel electrophoretic mobilities and amino acid composition. The primary structure of TP3 was determined by manual Edman degradation of the peptides obtained by lysyl endopeptidase-digestion or by alpha-chymotrypsin-digestion of RCM-TP3 from the testes, and by automated Edman degradation of it. Boar TP3 is a basic protein of 76 residues: H-AKVTEKSWQPQTTSTKRWKKRKTPSQPRSRGKVRKIYKKVKRPLHVCSRKKYSPKVITTSRRQKRAR RANKFETIP-OH, and it shows 27% homology with boar TP1. TP3 is composed of an N-terminal region (1-19) having two characteristic tryptophan residues (8 and 18) which is absent in the known TP1 group, and a C-terminal region (20-76) having a close resemblance to boar TP1.
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PMID:The amino acid sequence of a boar transition protein 3. 818 37

Bowman-Birk inhibitor analogues containing 2, 3 and 4-carbon analogues of the natural disulfide were synthesised via solid phase microwave-assisted RCM and found to have K(i) values against chymotrypsin in the low to sub-micromolar range, the best replacement for the disulfide arising from the linkage by RCM of two l-homoallylglycine residues.
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PMID:Synthesis and bio-assay of RCM-derived Bowman-Birk inhibitor analogues. 1474 52