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)

The cell-extracellular matrix junction, which includes the cell wall and the outer surface of the plasma membrane, may be an essential region for the perception of gravity by the internodal cells of Chara corallina. Typically, when an internodal cell is oriented vertically, the downwardly directed cytoplasmic stream travels at a velocity that is 10% faster than that of the upwardly directed stream. However when the cells are treated with impermeant hydrolytic enzymes that partially digest cellulose or hemicellulose, the cells lose their ability to respond to gravity even though streaming continues. By contrast, enzymes that digest pectins have no effect on the gravity-induced polarity of cytoplasmic streaming. Furthermore, gravisensing is sensitive to protease treatment; Proteinase K, thermolysin and collagenase but not trypsin, alpha-chymotrypsin or carboxypeptidase B, inhibit gravisensing. These findings indicate that proteins in the cell-extracellular matrix junction may be required for gravisensing. Moreover, the tetrapeptide Arg-Gly-Asp-Ser (RGDS) inhibits gravisensing in a concentration-dependent manner, indicating that the gravireceptor may be an integrin-like protein. The macromolecules necessary for gravisensing have been localized to the cell ends. As a consequence of the exoplasmic site of action of the enzymes and the tetrapeptides, we interpret the results to mean that they are acting on the gravireceptor, although we cannot eliminate the possibility that they are acting on the signal transduction chain. On the whole, our observations indicate that the cell-extracellular matrix junction is a sine qua non for graviperception in statolith-free Chara internodal cells and we suggest that the gravireceptor is located in this region.
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PMID:The contribution of the extracellular matrix to gravisensing in characean cells. 152 45

The differential cleavage of surface proteins of Borrelia burgdorferi IRS strains by several proteases was examined. Proteinase K, trypsin, chymotrypsin and thermolysin all cleaved the outer surface protein B (OspB) to undetectable levels by Coomassie Brilliant Blue staining, whereas some residual protein was detected by immunoblotting with polyclonal and monoclonal antibodies. Not even antigenic fragments were detectable by immunoblotting with 1A8 monoclonal antibody reactive with OspB. Less effective or ineffective was the cleavage of OspB by V8 protease and proteinase A, respectively. The outer surface protein A was cleaved only by proteinase K. The effect of trypsin on borreliae viability and adhesion to cultured cells was also studied. The trypsin treatment of borreliae did not impair the viability of organisms which continued to synthesize the cleaved OspB. The attachment of B. burgdorferi to HEp-2 cells was reduced by 41% after treatment with trypsin, whereas preincubation of borreliae with monoclonal antibody 1A8 and guinea pig immune serum reduced the adhesion of borreliae to the cells by 32% and 87%, respectively.
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PMID:Differential cleavage of surface proteins of Borrelia burgdorferi by proteases. 160 94

Proteinases and peptidases from the intestinal tract of fifth-instar larvae of Heliothis (= Helicoverpa) zea (Boddie) (Lepidoptera:Noctuidae) were characterized based on their substrate specificity, tissue of origin, and pH optimum. Activity corresponding to trypsin, chymotrypsin, carboxypeptidases A and B, and leucine aminopeptidase was detected in regurgitated fluids, midgut contents, and midgut wall. High levels of proteinase activity were detected in whole midgut homogenates, with much lower levels being observed in foregut and salivary gland homogenates. In addition, enzyme levels were determined from midgut lumen contents, midgut wall homogenates, and regurgitated fluids. Proteinase activities were highest in the regurgitated fluids and midgut lumen contents, with the exception of leucine aminopeptidase activity, which was found primarily in the midgut wall. Larvae fed their natural diet of soybean leaves had digestive proteinase levels that were similar to those of larvae fed artificial diet. No major differences in midgut proteinase activity were detected between larvae reared under axenic or xenic conditions, indicating that the larvae are capable of digesting proteins in the absence of gut microorganisms. The effect of pH on the activity of each proteinase was studied. The pH optima for the major proteinases were determined to be pH 8.0-8.5 for trypsin, when tosyl-L-arginine methyl ester was used as the substrate; and pH 7.5-8.0 for chymotrypsin, when benzoyl-L-tyrosine ethyl ester was used as the substrate.
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PMID:Digestive proteinases of larvae of the corn earworm, Heliothis zea: characterization, distribution, and dietary relationships. 179 75

The mitochondrial energy-linked nicotinamide nucleotide transhydrogenase is a homodimer of monomer Mr = 109,228. Hydropathy analysis of its cDNA-deduced amino acid sequence (1043 residues) has indicated that the molecule is composed of 3 domains: a 430-residue-long hydrophilic N-terminal domain which binds NAD(H), a 200-residue-long hydrophilic C-terminal domain which binds NADP(H), and a 400-residue-long hydrophobic central domain which appears to be made up mainly of about 14 hydrophobic clusters of approximately 20 residues each. In this study, antibodies were raised to the hydrophilic N- and C-terminal domains cleaved from the isolated transhydrogenase by proteolytic digestion, and to a synthetic, hydrophilic pentadecapeptide, which corresponded to position 540-554 within the central hydrophobic domain. Immunochemical experiments with mitoplasts (mitochondria denuded of outer membrane) and submitochondrial particles (inside-out inner membrane vesicles) as sources of antigens showed that essentially the entire N- and C-terminal hydrophilic domains of the transhydrogenase, as well as epitopes from the central pentadecapeptide, protrude from the inner membrane into the mitochondrial matrix, where the N- and C-terminal domains would be expected to come together to form the enzyme's catalytic site. Treatment of mitoplasts with several proteolytic enzymes indicated that large protease-sensitive masses of the transhydrogenase are not exposed on the cytosolic side of the inner membrane, which agreed with the exception that the central highly hydrophobic domain of the molecule should be largely membrane-intercalated. Trypsin, alpha-chymotrypsin, and papain had little or no effect on the mitoplast-embedded transhydrogenase. Proteinase K, subtilisin (Nagarse), thermolysin, and pronase E each split the mitoplast-embedded enzyme into two fragments only, a fragment of approximately 70 kDa containing the N-terminal hydrophilic domain, and one of approximately 40 kDa bearing the C-terminal hydrophilic domain. The cleavage site of proteinase K was determined to be A690 -A691, which is located in a small hydrophilic segment within the central hydrophobic domain. This protease-sensitive loop appears to be exposed on the cytosolic side of the inner membrane. The proteinase K-nicked enzyme containing two peptides of 71 and 39 kDa was isolated from mitoplasts and shown to have high transhydrogenase activity.
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PMID:Mitochondrial energy-linked nicotinamide nucleotide transhydrogenase. Membrane topography of the bovine enzyme. 200 10

Proteinase K-treatment of red blood cells either diminished or abolished the antigenic activities of glycophorin A and glycophorin B, and revealed the presence of a cryptic antigen that was recognized by antibody naturally existing in the autoplasma. About ninety five percent of all healthy persons have this autoantibody belonging to the IgM classification, whose titer ranges from 2 to 32. The activity of this autoantibody was absorbed by histidine and glutaminic acid. We were able to isolate this autoantibody from the plasma by means of an alkaline elution method and the autoantibody did not agglutinate chymotrypsin-treated red blood cells and red blood cells treated with chymotrypsin, following proteinase K-treatment. These results indicate that after proteinase K-treatment this autoantibody may not have an affinity for glycolipids, but for proteins digested by chymotrypsin.
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PMID:Blood group antigens transformed by proteinase K-treatment and the discovery of a natural autoantibody of these treated red blood cells. 223 30

A previous report from our laboratory indicated that a proteinase inhibitor is produced by rabbit T lymphocytes. We now report that a human T cell line, C91/PL, produces a proteinase inhibitor which inhibits the enzymatic activity of trypsin and kallikrein. This newly identified proteinase inhibitor (LPI 1) did not inhibit the enzymatic activity of four other serine proteinases (thrombin, plasmin, chymotrypsin, or pancreatic elastase), a thiol proteinase (papain), or a carboxyl proteinase (pepsin). Active synthesis of LPI 1 by the C91/PL cell line was shown by the appearance of similar levels of inhibitory activity in sequential cell supernatants, lack of appearance of inhibitor in supernatants of cells killed by heat or sodium azide or of viable cells in the presence of cyclohexamide, and incorporation of a radiolabeled amino acid into newly synthesized inhibitor. Although both the inhibitor of rabbit origin and of human origin are proteins produced by T cells and have similar inhibitory specificity, important differences were observed: LPI 1 is sensitive to boiling and the two inhibitors migrate differently upon electrophoresis in substrate-containing polyacrylamide gel. Furthermore, LPI 1 was produced by a cell line of the T4 phenotype which had been established by in vitro viral transformation of human cord blood lymphocytes with HTLV 1 whereas the inhibitor of rabbit origin was produced by normal splenic T cells. Three other human T cell lines of the T4 phenotype, MOLT-13, KE-37, and HPB-ALL, from patients with acute lymphoblastic leukemia did not produce a proteinase inhibitor. Thus, the production of proteinase inhibitors does not appear to be a general characteristic of human T cell lines nor of the T4 subset. Proteinase inhibitors produced by T cells may have an immunoregulatory role in proteinase-mediated physiological processes.
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PMID:A serine proteinase inhibitor produced by an HTLV I virus-transformed human T lymphocyte line. 243 46

Inter-alpha-trypsin inhibitor (I alpha I) is a unique proteinase inhibitor that can be proteolyzed by the same enzymes that are inhibited, to generate smaller inhibitors. This study examines the reactions of I alpha I with trypsin, chymotrypsin, plasmin, and leukocyte elastase. Complexes of I alpha I and proteinase were demonstrated by gel filtration chromatography. Complete digestion of I alpha I by each proteinase was not accompanied by a comparable loss of inhibition of that enzyme or a different enzyme. Following proteolysis, inhibitory activity was identified in I alpha I fragments of molecular weight 50,000-100,000 and less than 40,000. Addition of a second proteinase inhibitor prevented proteolysis. Both I alpha I and its complex with proteinase were susceptible to degradation. Kinetic parameters for both the inhibition and proteolysis reactions of I alpha I with four proteinases were measured under physiological conditions. On the basis of these results, a model for the mechanism of action of I alpha I is proposed: Proteinase can react with either of two independent sites on I alpha I to form an inhibitory complex or a complex that leads to proteolysis. Both reactions occur simultaneously, but the inhibitory capacity of I alpha I is not significantly affected by proteolysis since the product of proteolysis is also an inhibitor. For a given proteinase, the inhibition equilibrium constant and the Michaelis constant for proteolysis describe the relative stability of the inhibition and proteolysis complexes; the second-order rate constants for inhibition and proteolysis indicate the likelihood of either reaction. The incidence of inhibition or proteolysis reactions involving I alpha I in vivo cannot be assessed without knowledge of the exact concentrations of inhibitor and proteinases; however, analysis of inhibition rate constants suggests that I alpha I might be involved in plasmin inhibition.
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PMID:Mechanism of action of inter-alpha-trypsin inhibitor. 244 Apr 71

Sporothrix schenckii, mainly in the yeast form of the organism, produced extracellular proteinases when cultivated in liquid media containing albumin or collagen as a nitrogen source, but did not do so in brain heart infusion medium. Isolation of two extracellular proteinases from albumin-containing medium was performed by chromatography on DEAE-Sepharose CL-6B and Sephacryl S-200. Proteinase I had a molecular weight of 36,500, an optimal pH at 6.0, and a pI at 4.8. Despite its activities in weakly acidic conditions, proteinase I demonstrated chymotrypsinlike characteristics, these being indicated by strong inhibitory activity by phenylmethylsulfonyl fluoride and chymostatin and good kinetic constants for a synthetic chymotrypsin substrate, Suc-Ala-Ala-Pro-Phe-MCA. Proteinase II had a molecular weight of 39,000, an optimal pH at 3.5, and a pI at 3.8. Proteinase II showed cathepsin D-like characteristics, these being indicated by strong inhibitory activity by pepstatin, an acidic optimal pH, and good kinetic constants for hemoglobin. These two enzymes hydrolyzed natural substrates such as stratum corneum, type I collagen, and elastin although not type IV collagen. Proteinase production and cell growth in collagen-containing medium and the enzymatic digestion of skin constituents by isolated proteinases suggested that these two proteinases cooperatively enable the organism to invade skin and to obtain peptides from insoluble proteins.
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PMID:Isolation and properties of extracellular proteinases from Sporothrix schenckii. 330 79

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

Proteinase Inhibitor I was induced to accumulate in tobacco (Nicotiana tabaccum) leaves by placing plants in darkness for 10 days at 27 degrees C. The inhibitor was isolated using ammonium sulfate precipitation, Sephadex G-75 chromatography, heating, and affinity chromatography with a chymotrypsin-Sepharose column. Inhibitor I was purified 232-fold with a yield of 34 mg from 2.5 kg of leaves. Affinity-purified tobacco Inhibitor I was shown to be homogeneous by gel electrophoresis in both nondissociating and dissociating buffers. The inhibitor has a molecular weight of 39,000 +/- 1000 determined by gel filtration and, like its potato and tomato counterparts, is composed of five subunits of molecular weight 8100. The tobacco Inhibitor I strongly inhibits chymotrypsin and weakly inhibits trypsin. The chemical, physical, and immunological properties of tobacco Inhibitor I indicate that it is structurally very similar to potato tuber Inhibitor I and tomato leaf Inhibitor I, although the synthesis and accumulation of the three inhibitors in their respective tissues are all under different developmental or environmental regulation.
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PMID:Isolation and characterization of proteinase inhibitor I from etiolated tobacco leaves. 642 73


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