Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.27 (thermolysin)
 1,894 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

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

Streptomyces Metallo-Proteinase Inhibitor (S-MPI) consists of 102 amino acid residues, including one methionine and two disulfide bridges. The complete amino acid sequence of S-MPI, including two disulfide bridges, was determined by sequencing of tryptic and chymotryptic peptides of two fragments obtained by cyanogen bromide cleavage followed by reduction and S-pyridylethylation of the protein. Incubation of the inhibitor with thermolysin slowly cleaved one peptide bond, Cys(64)-Val(65), which might be a reactive site of S-MPI.
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PMID:Amino acid sequence of Streptomyces metallo-proteinase inhibitor from Streptomyces nigrescens TK-23. 388 72

The entire amino acid sequence of Ac1-Proteinase from Deinagkistrodon acutus venom was determined by using lysyl endopeptidase, metalloendopeptidase, trypsin and V8 protease. The hemorrhagic toxin had a typical zinc-chelating sequence His-Glu-X-X-His found in thermolysin.
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PMID:Primary structure of Ac1-proteinase from the venom of Deinagkistrodon acutus (hundred-pace snake) from Taiwan. 765 43

Proteinase K, subtilisin, pronase E, elastase, bactotrypsin, and thermolysin are all shown here to cleave native mitochondrial creatine kinase from chicken heart (Mib-CK) very specifically at a single site, either before or after Ala-323. In analogy with hen egg ovalbumin, where the same proteases all cleaved the polypeptide chain very specifically around Ala-352, Ala-323 of Mib-CK may be located in an exposed surface loop that is sensitive to protease attack. Gel permeation chromatography demonstrated that the two proteolytic fragments of Mib-CK with M(r)'s of approximately 37,000 and approximately 6000 remain associated with each other. Proteinase K cleavage did not influence the octamer to dimer ratio of Mib-CK, indicating that selective cleavage after Ala-323 has no direct effect on dimer-dimer interfaces within the octamer. However, upon addition of MgADP plus creatine and nitrate to induce a transition-state analogue complex of the enzyme, native Mib-CK dissociated much more readily into dimers than proteinase K-digested Mib-CK. Furthermore, proteinase K cleavage of Mib-CK resulted in 2-11-fold decreases in the Vmax values, as well as in 6-23-fold increases in the Km values for phosphocreatine, creatine, and MgATP, whereas the Kd values for both MgATP and creatine were unaffected. Consequently, proteinase K cleavage of Mib-CK does not affect substrate binding per se, but interferes with substrate-induced conformational changes which are essential for catalysis and which mediate the synergism in substrate binding as it is observed with the unmodified enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Limited proteolysis of creatine kinase. Implications for three-dimensional structure and for conformational substrates. 839 19

Pepsin successfully catalyzed the synthesis of several hydrophobic octa- and decapeptides in dimethylformamide-water solutions containing concentrated urea at pH 4.65. The factors that influence peptide synthesis in the presence of urea were studied using condensation of the tripeptides Z-Ala-Ala-Phe-OH and H-Leu-Ala-Ala-OCH3 as a model. The dependence of Z-Ala-Ala-Phe-Leu-Ala-Ala-OCH3 yield on pepsin concentration and pH, as well as the behavior of pepsin during peptide synthesis were studied. It was shown that pepsin catalyzed the synthesis of Z-Ala-Ala-Phe-Leu-Ala-Ala-OCH3 in guanidine hydrochloride and sodium dodecyl sulfate solutions. Other proteinases, subtilisin and thermolysin, were applied for the synthesis of p-nitroanilides of tri- and tetrapeptides in urea solutions. Proteinase-catalyzed peptide synthesis in the presence of denaturing agents might help to overcome the limitations caused by poor solubility of the starting peptide derivatives, although this effect is sometimes counterbalanced by the product solubility.
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PMID:Proteinase-catalyzed peptide synthesis in concentrated solutions of urea and other denaturing agents. 890 96