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

Isoproterenol-induced desensitization of turkey erythrocyte adenylate cyclase is accompanied (1) by a decrease in the mobility of beta-adrenergic receptor proteins, specifically photoaffinity labeled with 125I-(p-azidobenzyl)carazolol (125I-PABC), on sodium dodecyl sulfate (SDS)-polyacrylamide gels and (2) by a 2-3-fold increase in phosphate incorporation into the beta receptor [Stadel, J.M., Nambi, P., Shorr, R. G. L., Sawyer, D. F., Caron, M. G., & Lefkowitz, R. J. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 3173]. Analysis of 32P-labeled beta receptors partially purified by affinity chromatography and subsequently hydrolyzed in 6 N HCl revealed that the beta receptor from control erythrocytes contained only phosphoserine and that agonist-promoted phosphorylation of the receptor in desensitized cells occurred on serine residues. Comparison of limited-digest peptide maps of 125I-PABC-labeled beta receptors from control and desensitized erythrocytes reveals distinctly different sensitivities of the two beta receptors to cleavage by chymotrypsin and Staphylococcus aureus protease. The altered mobility of the 125I-PABC-labeled beta receptor from desensitized erythrocytes was eliminated when 5 M urea was included in the SDS-polyacrylamide gels. Limited-digest peptide mapping of 32P-labeled beta receptors from control and desensitized cells with the protease papain identified a unique phosphorylated peptide in desensitized preparations. Our results are consistent with the hypothesis that the altered mobility of beta-receptor proteins on SDS gels following desensitization is due to changes in conformation promoted by prolonged exposure to agonists.
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PMID:Biochemical characterization of phosphorylated beta-adrenergic receptors from catecholamine-desensitized turkey erythrocytes. 301 95

Benzoyl- and isopentenoyl phosphoric triamides (BPA and IPA) strongly inhibited urease activities from jack bean, soybean, watermelon seed, Proteus mirabilis, P. rettgeri, P. vulgaris, Mycobacterium smegmatis, and Ureaplasma urealyticum. Their I50 values (the final concentration causing 50% inhibition), independent of enzyme source, were 2-21 nM, which are about 1,000-fold lower than that of caprylohydroxamic acid, one of the most potent urease inhibitors. ATP-urea amidolyase activity was inhibited 50% by BPA at a higher concentration of 0.28 mM, but was not affected by IPA even at 1.3 mM. Thirteen kinds of hydrolases (trypsin, chymotrypsin, thermolysin, leucine aminopeptidase, papain, lipase, alpha-amylase, glucuronidase, asparaginase, arylsulfatase, alkaline phosphatase, acid phosphatase, and true cholinesterase), two oxidoreductases (catalase and alcohol dehydrogenase), three transferases (glutamic-oxaloacetic aminotransferase, gamma-glutamyl transpeptidase, and arylsulfotransferase) and two kinases (pyruvate kinase and creatine kinase) were not affected at all even at 1 mM BPA and IPA. Exceptionally, pseudo-cholinesterase from human serum was inhibited by BPA and IPA, whose I50 values were 70 nM and 10 muM, respectively, using acetylthiocholine as a substrate. These values increased to 0.55 muM and 54 muM, respectively, when acetylcholine was used as a substrate. These results show that N-acylphosphoric triamides potently and specifically inhibit urease activity at concentrations of nM order.
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PMID:Specific inhibition of urease by N-acylphosphoric triamides. 384 42

The extracellular matrix of cultured chicken embryo fibroblasts undergoes a number of modifications during the early stages of oncogenic transformation. One alteration is increased production of a small protein (Mr approximately 21,000) which is transiently deposited in the matrix by transforming cells infected with LA24, a temperature-sensitive mutant of Rous sarcoma virus (RSV) (Blenis, J., and Hawkes, S.P. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 770-774). This protein is a major component of substratum-associated material (material which remains attached to culture dishes after removal of cells with ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid). Its synthesis is stimulated by transformation of cells with NY68, another ts mutant of RSV, and also by treatment of normal, uninfected cells with the tumor promoter, phorbol myristate acetate. Accessibility of the 21-kDa protein to lactoperoxidase-catalyzed iodination indicates an exposed location within the matrix. The protein binds strongly to the culture dish and/or other matrix components. This interaction can be disrupted by sodium dodecyl sulfate but not by several nonionic detergents, unless beta-mercaptoethanol or KCl (0.5 M) are also present. High concentrations of urea or guanidine hydrochloride also remove the protein from the matrix. The 21-kDa protein is resistant to trypsin, collagenase, and the hydrolytic enzymes associated with cells transformed by the wild-type Prague A RSV but not to Pronase or chymotrypsin. A 21-kDa protein with properties similar to those described above is also detected in the medium and binds to the matrix, suggesting that a potential route of deposition of the 21-kDa protein in the matrix may be via shedding and subsequent interaction with other matrix components.
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PMID:Characterization of a transformation-sensitive protein in the extracellular matrix of chicken embryo fibroblasts. 643 99

A 21-kD protein isolated earlier from potato tubers (Solanum tuberosum L.) has two isoforms, with pI 6.3 and 5.2, which were separated by fast protein ion-exchange chromatography on a Mono Q column. The primary structures of the two forms consisted of 187 and 186 amino acid residues. Both isoforms are composed of two polypeptide chains, designated A and B, linked by a single disulfide bond between Cys-146 of the A chain and Cys-7 of the B chain. The amino acid sequences of the A chains of the two forms, consisting of 150 residues each, differ in a single amino acid residue at position 52 (Val --> Ile), while the B chains, containing 37 and 36 residues, respectively, have substitutions at nine positions (Leu-8 --> Ser-8, Lys-25--Asp-26 --> Asn-25--Glu-26, Ile-31--Ser-32 --> Val-31--Leu-32, Lys-34--Gln-35--Val-36--Gln-37 --> Gln-34--Glu-35--Val-36). Both isoforms form stable inhibiting complexes with human leukocyte elastase and are less effective against chymotrypsin and trypsin.
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PMID:Primary structure of a 21-kD protein from potato tubers. 1061 30