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 serine proteinase inhibitor from summer squash seeds (CPTI-II) with Mr of about 3250 contains three disulphide bridges and is unusually resistant to denaturing agents (e.g. 10% trichloroacetic acid at about 100 degrees C), thermolysin and proteinase V8 from Staphylococcus aureus. The inhibitor is digested by pepsin; the digestion of the virgin form proceeds more rapidly than when the peptide bond of the reactive site is broken. The inhibitor is not specifically reduced by sodium borohydride at pH 8.8, and almost full reactivation of the inhibitor reduced by dithiothreitol takes place at pH 8.15 in the presence of EDTA and the reduced + oxidized glutathione system. The inhibitor was crystallized from methanol. CD spectra point to the occurrence of beta-turns in the secondary structure of the inhibitor.
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PMID:The serine proteinase inhibitor from summer squash (Cucurbita pepo): some structural features, stability and proteolytic degradation. 393 87

The myxoma and malignant rabbit fibroma poxviruses are lethal tumorigenic viruses of rabbits whose virulence is modulated by the production of a virus-encoded secreted serine proteinase inhibitor, SERP-1. This viral protein was detected in medium harvested from myxoma and malignant rabbit fibroma virus-infected cells, and its inhibitory profile has been characterized by gel and kinetic analysis. SERP-1 forms complexes with and inhibits the human fibrinolytic enzymes plasmin, urokinase, and two-chain tissue-type plasminogen activator (association rate constants 3.4 x 10(4), 4.3 x 10(4), and 3.6 x 10(4) M-1 s-1 respectively). It is also able to inhibit C1S, the first enzyme in the complement cascade with an association rate constant which was unaffected by the addition of heparin (1.3 x 10(3) M-1 s-1). SERP-1 acts as a substrate for and is cleaved by thrombin, porcine trypsin, human neutrophil elastase, porcine pancreatic elastase, thermolysin, subtilisin, bovine alpha-chymotrypsin, and factor Xa. Incubation with kallikrein and cathepsin G had no effect. The structure of SERP-1 has been modeled on other members of the serpin family which revealed the characteristic serpin architecture apart from the absence of the D-helix. Structural analysis and kinetic assays demonstrate that the absence of this region does not prevent inhibitory activity and furthermore allow the identification of cysteine residues involved in internal and intermolecular disulfide bonding.
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PMID:Inhibition of plasmin, urokinase, tissue plasminogen activator, and C1S by a myxoma virus serine proteinase inhibitor. 841 56

A novel thermostable neutral proteinase, called NPS, was purified to electrophoretic homogeneity from the culture broth of Saccharomonospora canescens sp. novus, strain 5. The molecular mass was determined by SDS-polyacrylamide gel electrophoresis to be 35,000 Da. The enzyme exhibits a sharp pH optimum of proteolytic activity at pH 6.7. NPS was completely inactivated with inhibitors, typical for metalloendopeptidases, EDTA and 1,10-phenantroline, whereas the serine proteinase inhibitor PMSF had no effect. Atomic absorption measurements showed that the proteinase binds a single zinc and four calcium ions. The enzyme thermostability was characterized in the absence and presence of added calcium. Melting temperature, Tm = 77 degrees C and an activation energy, Ea, for the thermal deactivation of the excited protein fluorophores of 72.13 kJ mol-1 were calculated in the presence of 100 mM CaCl2. The Ea-value is considerably higher than those obtained for a number of proteinases from microorganisms and was explained by the thermostable structure of the enzyme. Effective radiationless energy transfer from phenol groups to indole rings was observed. 68% of the light absorbed by tyrosyl residues is transferred to tryptophyl side chains. No homology was found after comparison of the NPS N-terminal sequence, including the first 26 residues, with those of other neutral proteinases from microorganisms. In contrast to the well-known bacterial neutral proteinase thermolysin and related enzymes from microorganisms, NPS possesses arylamidase and esterase activities. Further crystallographic studies will reveal the structural reasons for this specificity. Epoxy and epithio pyranosides are inhibitors of the proteinase arylamidase activity.
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PMID:A novel thermostable neutral proteinase from Saccharomonospora canescens. 954 Jul 92