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)

Trypsin digestion of pertussis toxin (PT) preferentially cleaved the S1 subunit at Arg-218 without detectable degradation of the B oligomer. The fragment produced, termed the tryptic S1 fragment, appears to remain associated with the B oligomer. Chymotrypsin digestion of PT also preferentially cleaved the S1 subunit without detectable degradation of the B oligomer. The chymotryptic S1 fragment possessed a slightly lower apparent molecular weight than the tryptic S1 fragment and was more accessible to the respective protease. Trypsin- and chymotrypsin-treated PT and PT required the presence of dithiothreitol and ATP for optimal enzymatic activity. Trypsin-treated PT showed approximately a 2-4-fold higher level of expression of ADP-ribosyltransferase and NAD-glycohydrolase activities than PT. Chymotrypsin-treated PT also exhibited approximately a 2-fold greater level of ADP-ribosyltransferase activity than PT. The observed increase in activity of protease-treated PT was due primarily to a shorter time for activation in PT mediated ADP-ribosylation of transducin. In addition, trypsin-digested PT possessed the same cytotoxic potential for Chinese hamster ovary cell clustering as PT. One possible role for the generation of a proteolytic fragment of the S1 subunit of PT would be to produce a catalytic fragment with increased efficiency for ADP-ribosylation of G proteins in vivo.
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PMID:Protease treatment of pertussis toxin identifies the preferential cleavage of the S1 subunit. 185 Jul 38

Chymotrypsin (EC 3.4.21.1) powder suspended in hexane in the presence of Na2CO3.10H2O is a good catalyst for peptide synthesis. The salt hydrate releases water to fix the thermodynamic water activity of the system in accord with its dissociation pressure. Salt hydrates can be useful to buffer water activity in mainly organic enzyme reaction mixtures at a value permitting activity of the catalyst while minimising hydrolytic side reactions.
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PMID:Salt hydrates buffer water activity during chymotrypsin-catalysed peptide synthesis. 185 22

Keratinocytes comprise the majority of cells in the epidermis, the interleukin-1 rich layer of tissue contiguous with the outside world. Keratinocytes produce IL-1 alpha and beta mRNA in vitro, but only IL-1 alpha biological activity has been identified in keratinocyte cultures. In contrast, monocytes secrete biological activities attributable to both species of IL-1. Using several monoclonal antibodies to IL-1 beta, significant amounts of IL-1 beta protein could be found in keratinocyte cultures; all of this immunoreactive IL-1 beta was in the 31-kD form. This latent cytokine has been shown to bind inefficiently to the IL-1 receptor and to be (in relative terms) biologically inactive. Chymotrypsin cleaves 31-kD IL-1 beta at Tyr 113-Val 114, generating an 18-kD IL-1 species with activity equivalent to the authentic mature IL-1 beta (NH2-terminal Ala 117). Treatment of 31-kD keratinocyte IL-1 beta with chymotrypsin also generated an 18-kD molecule and significant IL-1 activity. Monocytes contain an IL-1 convertase enzyme that cleaves the IL-1 beta promolecule at Ala 117. We demonstrate here that keratinocytes do not contain such an IL-1 convertase activity, nor do they contain any activity capable of productively processing 31-kD IL-1 beta into a biologically active form. These data suggest that keratinocytes (and other non-bone marrow-derived cells) produce IL-1 beta in an inactive form that can be processed only after leaving the cell.
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PMID:Human keratinocytes produce but do not process pro-interleukin-1 (IL-1) beta. Different strategies of IL-1 production and processing in monocytes and keratinocytes. 199 87

The rate and extent of insulin degradation by trypsin and alpha-chymotrypsin were examined in vitro, and the initial sites of cleavage by alpha-chymotrypsin were identified. The apparent Km for both enzymes was approximately the same but the apparent Vmax for alpha-chymotrypsin was 8.6 times greater. At a molar ratio of 172:1 (insulin:enzyme), chymotrypsin caused near-total loss of insulin within 40 min, while very little insulin was degraded by trypsin. Chymotrypsin appeared to cleave initially at the carboxyl side of the B26-Tyr and A19-Tyr residues, and additional cleavage at the B16-Tyr, B25-Phe, and A14-Tyr residue sites also occurred rapidly. Only two to three other susceptible bonds, which are not exposed at the surface of the insulin molecule, remained intact after the quenching of initial cleavage. Four of the amino acids involved in initial cleavage are essential for receptor binding ability, making it difficult to modify insulin chemically to achieve greater stability without losing activity.
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PMID:Degradation of insulin by trypsin and alpha-chymotrypsin. 206 1

Antibody blocking studies in the mouse suggest that the MEL-14 antigen is involved in neutrophil-endothelial cell interactions and may be important in neutrophil extravasation to sites of inflammation in vivo. We recently showed that chemotactic factor activation causes a rapid (within minutes) shedding of a large fragment of the MEL-14 antigen from the surface of neutrophils. We report here that chymotrypsin, at low doses (0.1 units/1 x 10(6) cells), but not trypsin, elastase, or collagenase, causes an activation-independent rapid loss (greater than 90%) of the MEL-14 antigen from the surface of murine neutrophils. Under the same treatment conditions chymotrypsin has no effect on the expression of four other neutrophil surface antigens, including the Mac-1 adhesion protein. Chymotrypsin treatment has no effect on neutrophil adhesion to plastic, migration to C5a, regulation of the Mac-1 antigen, but causes a greater than 95% reduction in neutrophil binding to high endothelial venules (HEV) in peripheral lymph nodes measured in the ex vivo frozen section HEV binding assay. The level of inhibition of neutrophil adhesion to HEV was comparable to that seen with the MEL-14 antibody. This experimental system allows us for the first time to specifically examine the consequences of removing the MEL-14 antigen from the surface of neutrophils on function in vivo. We show that treatment with chymotrypsin blocks greater than 85% of the ability of neutrophils injected back into the animal to home to the inflamed peritoneum. In similar in vivo experiments the MEL-14 antibody blocks neutrophil homing by 60-70%. These results further support the importance of the MEL-14 antigen in neutrophil extravasation in vivo and indicate that chymotrypsin could be useful in examining the molecular mechanisms involved in extravasation of leukocytes into a variety of diverse tissue sites of inflammation.
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PMID:Low-dose chymotrypsin treatment inhibits neutrophil migration into sites of inflammation in vivo: effects on Mac-1 and MEL-14 adhesion protein expression and function. 206 57

Lymphokine activated killer (LAK) cells mediate the lysis of a variety of histologically distinct tumor targets. We investigated the nature and diversity of the structures involved in the recognition phenomenon by evaluating the effects of treating effector and target cells with trypsin and chymotrypsin, enzymes that disrupt surface protein molecules. Chymotrypsin and trypsin treatment of B16 target cells, a murine melanoma cell line, significantly abolished killing by LAK cells. Alternatively, neither of these treatments in P815 cells, a murine mastocytoma cell line, affected killing by LAK cells. Moreover, we found a differential effect of both these enzymes on YAC-1 cells, a murine leukemia cell line, with trypsin having a less inhibitory effect on cytolysis than chymotrypsin. The nature of the LAK cell receptor that presumably plays a role in binding target antigen was also investigated. Treatment of LAK cells with chymotrypsin significantly reduced lysis of the B16 and YAC-1 target cell types. However, trypsin treatment of the effectors only inhibited killing of the B16 tumor cell line. Cytotoxicity exerted against YAC-1 remained unaltered upon trypsinization of LAK cells. These cumulative results indicate heterogeneity of both the receptors on the LAK cells and the surface antigen molecules recognized on these targets. The use of YAC-1 as a target provided us with a tool to compare the LAK with the natural killer (NK) systems. The overall effect of proteolytic enzyme treatment in reducing cell lysis was more pronounced in the NK than in the LAK system.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Heterogeneity of cell surface structures involved in cytotoxicity mediated by lymphokine activated killer cells. 218 Oct 73

Serine proteinases have the potential to influence the degradation of connective tissue in chronic periodontitis, which may progress episodically at individual tooth sites. Elastase-, chymotrypsin- and tryptase-like proteinase activity in homogenized gingival tissue were measured using, respectively, the selective peptide substrates MeOSuc-Ala-Ala-Pro-Val-AFC. MeOSuc-Phe-Pro-Phe-AFC and Z-Ala-Arg-Arg-AFC. Each tooth site was assayed separately and divided, where appropriate, into gingival tissue and granulomata. Elastase-like activity was detected in only about half of the sites and with large variations. Chymotrypsin-like activity decreased with increasing pocket depth, clinical attachment level, gingival index and gingival bleeding index. Tryptase-like activity did not vary consistently with clinical measures. Chymotrypsin- and tryptase-like proteinase activity were much higher in gingival tissue than in granulomata. These effects are best explained by the likely influence (or lack of influence) of the endogenous serum and tissue inhibitors of serine proteinases, the different cellular origins of the enzymes, and their relative affinities for their substrates.
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PMID:A biochemical study of serine proteinase activities at local gingival tissue sites in human chronic periodontitis. 220 77

Alpha-chymotrypsin-catalyzed acyl transfer from Boc-L-MetONp, Ac-L-TyrOEt, Bz-L-TyrOMe, Mal-L-PheOMe to the C-protected amino acids (L-AlaNH2, L-LeuNH2, L-ArgOMe and beta-naphthylamides of L-Arg, L-Leu, L-Ala and L-Glu) has been studied. Modification of the carboxylic groups with beta-naphthylamide was shown to increase the reactivity of nucleophiles in these reactions by a factor of more than 100 in comparison with amides and esters of the same amino acids. This effect can be accounted for by the effective formation of the nucleophile-acylenzyme complex due to hydrophobic interactions of the beta-naphthylamide moiety with the corresponding subsite of alpha-chymotrypsin. The reaction kinetics follows the scheme involving hydrolysis of the nucleophile-acylenzyme intermediate. The contribution of this pathway depends on the structures of both the acyl-group donor and the added nucleophile. The competitive inhibition by amino acid beta-naphthylamides is also observed. The results obtained show that modification of the COOH-group of added nucleophiles by beta-naphthylamide strongly affects the reactivity of these compounds in the alpha-chymotrypsin-catalyzed peptide synthesis.
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PMID:Increased nucleophile reactivity of amino acid beta-naphthylamides in alpha-chymotrypsin-catalyzed peptide synthesis. 222 49

The susceptibility of the progesterone receptor, liganded either by the antiprogestin RU 486 or by the progestin ORG 2058, to chymotrypsin and trypsin degradation was investigated. The nuclear fraction was isolated from T47D cells previously exposed either to 0.1 microM [3H]RU 486 or to 0.1 microM [3H]ORG 2058. The proteolytic digestion was performed on the micrococcal nuclease hydrolysate. The molecular weights of the receptor fragments were calculated, in high salt buffer, from the sedimentation coefficients determined on a sucrose gradient and from the Stokes radii estimated by gel filtration on an Agarose A-0.5 m column. Micrococcal nuclease solubilized receptor forms with molecular weights of 80,000 and 75,000 for the antiprogestin- or progestin-liganded receptor, respectively. Chymotrypsin degraded these receptor forms to fragments with molecular weights of 23,000 either for the antiprogestin- or progestin-liganded receptor. Similar molecular weights of 23,000 were calculated for the progesterone receptor liganded either by the antiprogestin RU 436 or the progestin ORG 2058 following trypsin cleavage. We conclude that the degradation pattern of the progesterone receptor liganded either by the antiprogestin RU 486 or the progestin ORG 2058 following chymotrypsin or trypsin digestion seems to be similar.
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PMID:Comparison of the physical properties of the nuclear progesterone receptor, bound to antiprogestin RU 486 or progestin ORG 2058, following limited proteolysis. 238 53

Limited proteolysis of phospholipid complexes of heart and muscle bovine lactate dehydrogenase by trypsin and chymotrypsin has been studied under nondenaturing condition at pH 7.5. Chymotrypsin cleaves the polypeptide chain of heart and muscle lactate dehydrogenase into two principal fragments and LDH subunits were protected by lipids towards the proteinase attack. Enzymatic activity of heart and muscle lactate dehydrogenase was abolished by limited proteolytic cleavage. In complexes, both isoenzymes were protected against proteinases attack by lipids.
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PMID:Limited proteolysis of bovine muscle and heart lactate dehydrogenase is inhibited by phospholipid liposome interaction. 239 38


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