Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.86 (clotting enzyme)
 176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human alpha-thrombin, the two (covalently linked)-chain, highly coagulant blood-clotting enzyme was compared with its noncoagulant, yet estero/amidolytically active derivative, gamma-thrombin, a three (noncovalently associated)-domain enzyme which results from two proteolytic cleavages of the coagulant a form. Studies of their denaturation behavior by Tos-Arg-OMe esterase activity, by intrinsic fluorescence, by fluorescence of active serine-directed dansyl labels, and by monitoring the ESR of a fluorosulfonylphenyl spin-labeled inhibitor clearly demonstrated the reduced stability of the noncovalently associated gamma-thrombin form. At pH 6.5, 0.75 M NaCl, gamma-thrombin unfolds in approximately 2. 1 M urea while the more stable a form denatures at approximately 4 M urea. By monitoring active serine probes (spin label or fluorescent labels), these transitions were slightly lower, 1.0 +/- 0.1 and 2.8 +/- 0.2 M urea for spin-labeled gamma- and alpha-thrombins, respectively. Similar behavior was found for the same spin-labeled derivatives in guanidine HCl with unfolding transitions of 0.4 M and 1.0 M for spin-labeled gamma- and alpha-thrombin, respectively. These differences in structural stabilization serve as a good physical diagnostic for the two thrombin species.
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PMID:Stability differences between high coagulant (alpha) and noncoagulant (gamma) human thrombins. Denaturation. 624 51

A concentrate of milk-clotting enzyme was produced by culture of Mucor bacilliformis on wheat bran medium moistened to 120% water on dry bases with HC1 2 N solution. The wheat bran was autoclaved, spread on trays and inoculated with 5.10(6) spore/gr of dry bran. After 10 days of culture at 21 degrees C, the enzyme produced was extracted with water and adjusted to pH 4.4. The precipitation was performed with ethanol. The precipitate was dissolved in HCl solution (pH 4.5) and it was concentrated by dialysis against polyethylene glycol 20.000. The enzyme solution had a specific activity of 1123 units/mg. and it was tested in the elaboration of cream cheese.
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PMID:[Production of a concentrate of Mucor bacilliformis acid protease]. 676 21

A new endogenous serine proteinase from the cell-free hemolymph of a solitary ascidian, Halocythia roretzi, was purified by a combination of ammonium sulfate fractionation, hydrophobic interaction chromatography on TSKgel Toyopearl HW 65 F, ion exchange chromatography on TSKgel DEAE-Toyopearl 650 M, affinity chromatography on Arginine-Sepharose 4B, gel filtration on TSKgel Toyopearl HW 65F and hydroxyapatite chromatography on Bio-Gel HT. The serine proteinase is a single polypeptide chain whose molecular weight and isoelectric point are 39 kDa and about 7.6 pI, respectively. The most susceptible substrate was Boc-Leu-Gly-Arg-4-methyl-coumaryl-7-amide (MCA), and activity was optimal at pH 8. The enzyme was relatively stable at high temperatures; about 50% activity was retained even at 60 degrees C for 30 min in 50 mM Tris-HCl, pH 8.0, containing 0.5 M NaCl, and 0.05% Brij-35. The enzyme was characterized by the inhibitory effects of synthetic or natural inhibitors, substrate specificity toward 26 peptidyl-MCAs, proteinase activity toward natural proteins and complex formation with a serine proteinase inhibitor (58 kDa) previously found in H. roretzi hemolymph, indicating that the enzyme was a member of serine proteinases and strongly inhibited by the 58 kDa serine proteinase inhibitor as well as human antithrombin III. We also demonstrated the clotting enzyme activity of the purified serine proteinase toward bovine fibrinogen and Limulus coagulogen, a fibrinogen-like clottable protein of horseshoe crabs.
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PMID:Purification and characterization of a 39,000-Da serine proteinase from the hemolymph of a solitary ascidian, Halocynthia roretzi. 941 2