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)

Carboxypeptidase Y hydrolyzed N-substituted peptide-4-methylcoumarin-7-amides (peptide-NH-Mec) at pH 7 by releasing 7-amino-4-methylcoumarin (NH2-Mec) which was then followed by carboxypeptidase action. In particular, a chymotrypsin-directed substrate, Suc-Leu-Leu-Val-Tyr-NH-Mec, was hydrolyzed by the enzyme with a second-order rate constant of 7200 M-1 s-1, which is compatible with the rate for an anilide substrate and some N-substituted dipeptides. The activity was completely inhibited by phenylmethylsulfonyl fluoride and competitively depressed by the presence of an N-substituted dipeptide. Dependences of kinetic parameters on pH were different from those of carboxypeptidase, esterase, amidase, and anilidase activities. Carboxypeptidases P from Penicillium janthinellum and W from wheat also hydrolyzed some of these peptide-NH-Mec derivatives in a similar manner but at a rather low rate. Thus, the NH2-Mec-releasing activity may be considered to be intrinsic to serine carboxypeptidases in general. Taking into consideration this endopeptidase-like activity of serine carboxypeptidases, fluorogenic substrates should be used carefully to specify endopeptidases in crude extracts.
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PMID:Action of serine carboxypeptidases on endopeptidase substrates, peptide-4-methyl-coumaryl-7-amides. 390 5

One way in which serum promotes survival of primary cultured hepatocytes is by inhibiting plasma membrane protease (Nakamura, T., Asami, O., Tanaka, K., and Ichihara, A. (1984) Exp. Cell Res. 155, 81-91). One of these proteases was solubilized from the plasma membranes of rat liver with 4% octyl glucoside and purified to a homogeneous state by affinity chromatography on bovine pancreatic trypsin inhibitor linked to Sepharose 4B. The protease had an apparent Mr = 120,000 by Sephacryl S-200 gel filtration and the Mr of its subunits was 30,000, as determined by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. It appeared to be a glycoprotein. A high concentration of detergent was necessary to keep the protein soluble. The purified enzyme readily hydrolyzed synthetic tripeptide nitroanilides at sites adjacent to Arg or Lys residues, but did not degrade synthetic substrates of chymotrypsin, elastase, or aminopeptidase. It showed endopeptidase activity, hydrolyzing various proteins such as casein, hemoglobin, and denatured albumin. The enzyme was strongly inhibited by diisopropyl fluorophosphate, phenylmethanesulfonyl fluoride, bovine pancreatic trypsin inhibitor, leupeptin, antipain, and alpha 1-antitrypsin, but not by chymostatin, elastatinal, or inhibitors of carboxyl, thiol, or metallo proteases, suggesting that it is a seryl trypsin-like protease. This protease was found in plasma membranes of rat and mouse liver and in small amounts in those of kidney, but not in those of brain, red cells, Ehrlich ascites tumor, or two Morris hepatomas, suggesting that it may be involved in differentiated functions of normal hepatocytes.
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PMID:A unique trypsin-like protease associated with plasma membranes of rat liver. 394 38

Electrical field stimulation (EFS) depolarizes nerves and causes chloride secretion by mucosa of rabbit ileum mounted in a flux chamber. To test the hypothesis that the transmitter is a peptide, we determined whether the EFS response was prevented by the endopeptidase chymotrypsin (CT). Serosal, but not mucosal, addition of CT (200 micrograms/ml) reduced the short-circuit current (Isc) response to EFS by 90% or more. CT also reduced Cl absorption by decreasing the mucosal-to-serosal flux, but it did not affect net Na absorption. CT prevented the response to vasoactive intestinal polypeptides, but the response returned when CT activity was eliminated. The response to EFS did not return, however, implying that CT damaged cells that released transmitter or epithelial target cells. CT reduced the Isc response to serotonin by 69% and to A23187 by 10% and did not affect the theophylline response. We conclude that 1) the effects of CT on cell function limit its usefulness in identifying peptide neurotransmitters in epithelium, 2) CT irreversibly inhibits ion transport responses to EFS and to serotonin, and 3) CT reduces absorption of Cl probably by affecting a calcium pathway that modifies Cl transport.
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PMID:Chymotrypsin, ileal chloride transport, and neurotransmitters. 614 17

Considerable attention has been focused recently on alpha 2-macroglobulin (alpha 2M), a major endopeptidase inhibitor in blood plasma, as a possible source of the primary defect in cystic fibrosis (CF). We report here studies designed to compare the structure of CF alpha 2M with normal alpha 2M to determine if there is a difference. The physicochemical properties of purified alpha 2M as revealed by various electrophoretic techniques, covalent proteinase binding properties, and primary structural studies on a variety of partial hydrolyzates of CF alpha 2M and normal alpha 2M are compared. These studies were carried out on eight different individual isolates of CF alpha 2M and three age-matched normal alpha 2M preparations and alpha 2M isolated from fetal cord blood. Three properties of CF alpha 2M were studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE): (1) the existence of four identically-sized subunits in the native molecule (10), (2) the cleavage of this subunit into fragments of approximately 100,000 daltons upon interaction with proteinases (10), and (3) the cleavage of an alkaline/heat sensitive bond to produce 120,000 and 60,000 dalton fragments (11). Both CF and normal alpha 2M were cleaved to the extent of 79-87%, CF alpha 2M behaves identically with normal alpha 2M with regard to all these properties. Salvesen and Barrett (24) have demonstrated that varying proportions of several [125I]-labeled proteinases form SDS-stable, non-reducible links to normal alpha 2M. Two of the CF alpha 2M preparations were studied to determine if similar covalent binding of proteinases occurred. The positions of the labeled and % of proteinase bound bands in SDS/reduced PAGE system were identical for normal alpha 2M and CF alpha 2M. These results indicate that CF alpha 2M behaves normally with regard to covalent binding of proteinases. Qualitative comparison of the peptide fragments separated by SDS-PAGE or isoelectric focusing of CF and normal alpha 2M produced by partial proteolysis with trypsin, chymotrypsin or Staphylococcus aureus V-8 proteinase did not reveal any difference unique to CF alpha 2M. The cyanogen bromide fragmentation studies and the cysteine cleavage studies also indicated that no major change in the positions of methionyl residues or cysteinyl/cystinyl residues has occurred in CF alpha 2M. The failure of all these different studies and those reported by others to demonstrate any differences between CF and normal alpha 2M makes it highly unlikely that there is a primary defect in alpha 2M in CF.
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PMID:Comparison of the structure and aspects of the proteinase-binding properties of cystic fibrotic alpha-macroglobulin with normal alpha 2-macroglobulin. 617 35

Pancreatic amylase, elastase 1, elastase 2, cationic trypsin, chymotrypsin, ribonuclease (RNase), phospholipase A2, gamma-glutamyl transpeptidase (gamma-GTP) and pancreatic secretory trypsin inhibitor (PSTI) were purified and characterized from human pancreatic juice and pancreatic tissue. During the purification of these enzymes, two enzymes previously not reported were found. A pancreatic deamidase and a renal endopeptidase were purified and characterized. Specific and reliable radioimmunoassays (RIAs) were developed for all pancreatic enzymes and inhibitor. The purpose of immunoassay for pancreatic enzymes and inhibitor was discussed, and clinical application for the diagnosis of pancreatic diseases was demonstrated. Messenger RNA (mRNA) of amylase was isolated from human pancreas and parotid gland, and used to prepare a complementary DNA (cDNA). The nucleotide sequence and the predicted amino acid sequence of these clones were now being determined. The application of the present investigation to elucidation of pathogenesis of pancreatic enzyme-producing diseases was discussed.
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PMID:[Purification and development of immunoassay of pancreatic enzymes and trypsin inhibitor, and their application to elucidation of pathogenesis of various pancreatic and pancreatic enzyme-producing diseases]. 620 25

A specific antibody subpopulation(s) in antihorse cytochrome c serum was detected for peptide fragment 81-104 of cyanogen bromide (CNBr) cleaved horse cytochrome c (HCytc). This antiserum was made in the rabbit against polymeric horse cytochrome c. The presence of the peptide-specific antibody subpopulation(s) was demonstrated utilizing HCytc, CNBr-peptide 81-104 and isolated chymotrypsin-digested HCytc fragments 60-67, 83-97 and 98-104 to compete with radio-labeled peptide 81-104 and antiHCytc serum in a competitive radioimmunoassay (RIA). This antibody subpopulation(s) in antiHCytc serum was demonstrated to be specific for peptide 81-104. At the 50% inhibition level in competitive RIA, 100- and 1000-fold molar excesses of HCytc and its peptide 1-65, respectively, were required to affect an equivalent binding to that of the HCytc peptide 81-104. Competitive RIAs have been performed utilizing three different kinds of antigen to compete with HCytc peptide 81-104 and antihorse cytochrome c sera. These three kinds of antigens are: endopeptidase digests of HCytc, cytochrome c peptides 81-104 of several species and several isolated chymotryptic peptide fragments of HCytc. The results have indicated that this peptide-specific antibody subpopulations(s) in antiHCytc serum is similar to antibodies made against peptide 81-104-BSA. Regions of antigenicity have been identified at positions 92, 100, 103 and 104 with both antisera.
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PMID:Antibody subpopulation in antihorse cytochrome c serum. 620 69

One of the esteroproteinases present in the submandibular glands of female mice was purified and characterized. The enzyme, designated proteinase F in this report, had a pI value of 4.6 and a molecular weight of 27600, being comprised of two subunits of 10000 and 18000 daltons. The amino acid composition of proteinase F resembled that of the epidermal growth factor-binding protein, but antiserum against proteinase F only reacted weakly against the binding protein. Proteinase F had an optimum pH at around 9.0 and was strongly inhibited by Cu2+ and Hg2+ (42 and 76% inhibition, respectively, at a concentration of 4 x 10(-6) M). It was also inhibited by aprotinin, phenylmethylsulfonylfluoride, iodoacetamide, leupeptin, antipain, and benzamidine but neither by trypsin inhibitors from pancrease, soybean, or ovomucoid, nor by TLCK, TPCK, and epsilon-amino-n-caproic acid. Although its actual physiological function has yet to be determined, these properties indicate that proteinase F is a new enzyme, being distinguished from known proteinases, kallikrein, plasmin, trypsin, chymotrypsin, tonin, angiotensin-converting enzyme, proteinase A (beta-nerve growth factor endopeptidase), proteinase D (epidermal growth factor-binding protein), P-esterase, renin A, and renin C. Proteinase F was present in the submandibular glands of female mice more abundantly than in those of males, but it increased in males following castration. Thus, proteinase F appears to be affected by male hormones in vivo.
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PMID:A new esteroproteinase (proteinase F) from the submandibular glands of female mice. 633 33

The complete amino acid sequence of the endopeptidase II from the larvae of the hornet, Vespa orientalis, has been determined. The enzyme is a single polypeptide chain of 216 residues. The protease is a serine endopeptidase. When aligned for optimal homology to the trypsin related proteases, the insect endopeptidase displays 37% identity with bovine chymotrypsin. The structure of the hornet protease is the first reported for a serine endopeptidase from an insect.
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PMID:Amino acid sequence of an insect chymotrypsin from the larvae of the hornet, Vespa orientalis. 634 Jun 63

A neutral endopeptidase which degrades luteinizing hormone-releasing hormone (LH-RH, <GLu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-GLy-NH2) has been purified 900-fold from extracts of bovine anterior pituitary. This Ca2+-independent enzyme of 83 000 molecular weight (as estimated by gel filtration) cleaves LH-RH (KM = 180 microM) at the Tyr5-Gly6-His2-Trp3 bonds. Its activity is inhibited by the SH-reactive agents N-ethylmaleimide and p-(chloromercuri)benzoate but not by the OH-reactive agent diisopropyl fluorophosphate. Hydrolysis of the fluorogenic chymotrypsin substrate glutarkyl-Gly-Gly-Phe-beta-naphthylamide by this endopeptidase could not be detected. These properties differentiate the endopeptidase from chymotrypsin and from a glutaryl-Gly-Gly-Phe-beta-naphthylamide hydrolyzing activity of high molecular weight, which has been isolated from the same tissue and also hydrolyzes internal bonds of LH-RH.
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PMID:Characterization of a nonchymotrypsin-like endopeptidase from anterior pituitary that hydrolyzes luteining hormone-releasing hormone at the tyrosyl-glycine and histidyl-tryptophan bonds. 699 98

The substrate specificity of a peptidase from anterior pituitaries that is capable of hydrolyzing luteinizing hormone-releasing hormone (LH-RH; less than Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) at the Tyr5-Gly6 peptide bond has been investigated by using inhibitors and model substrates. While trypsin and chymotrypsin inhibitors from plants and animals are without any effect, many microbial protease inhibitors and synthetic peptides containing hydrophobic and basic amino acids inhibit the degradation of radiolabeled LH-RH by this enzyme. The model substrates N-acetyl-Phe-Gly-Leu-beta-naphthylamide, N-acetyl-Leu-Gly-Leu-beta-naphthylamide, and N alpha-benzoyl-Arg-Gly-Leu-beta-naphthylamide are hydrolyzed at the X-Gly peptide bonds; N-acetyl-Gly-Gly-Leu-beta-naphthylamide is not degraded. Hydrolysis of typical amino- and carboxypeptidase substrates was not observed. Degradation of the general protease substrates insulin B chain and denatured hemoglobin also could not be detected. Thus, the enzyme is not LH-RH specific but may be characterized as an endopeptidase that hydrolyzes peptides preferentially at the carboxyl terminus of hydrophobic and basic amino acids.
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PMID:Substrate specificity of an adenohypophyseal endopeptidase capable of hydrolyzing luteinizing hormone-releasing hormone: preferential cleavage of peptide bones involving the carboxyl terminus of hydrophobic and basic amino acids. 704 67


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