Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
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 fibrinogen-clotting enzyme, Jararacussin-I, was purified from the venom of Bothrops jararacussu by a combination of ion exchange chromatography using Resource 15S resin and affinity chromatography using Benzamidine Sepharose 6B resin. Jararacussin-I displays a molecular mass of 28 kDa as estimated by sodium dodecyl sulphate-PAGE and possesses an isoelectric point of 5.0. The coagulant specific activity of the enzyme was determined to be 45.8 NIHU/mg using bovine fibrinogen as the substrate and the esterase specific activity was determined to be 258.7 U/mg. The protease inhibitors, benzamidine and DTT inhibited the esterase specific activity by 72.4 and 69.7%, respectively. The optimal temperature and pH for the degradation of both chains of fibrinogen and esterase specific activity were determined to be 37 degrees C and 7.4-8.0, respectively. The enzyme was inactivated at both 4 and 75 degrees C. Single crystals of Jararacussin-I were obtained and complete three-dimensional X-ray diffraction data was collected at the Brazilian National Synchrotron Source (LNLS) to a resolution of 2.4A.
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PMID:Purification, characterization and crystallization of Jararacussin-I, a fibrinogen-clotting enzyme isolated from the venom of Bothrops jararacussu. 1222 Jul 16