The action of thrombin on intact human platelets has been studied with the aid of polyacrylamide gel electrophoresis in sodium dodecylsulfate. A single major membrane protein band with a molecular weight of 190,000 disappears after thrombin treatment, while a new membrane protein with a molecular weight of 107,000 appears. This may represent hydrolysis of the thrombin-sensitive protein. When pl...

BACKGROUND Acidosis, a frequent complication of trauma and complex surgery, results from tissue hypoperfusion and IV resuscitation with acidic fluids. While acidosis is known to inhibit the function of distinct enzymatic reactions, its cumulative effect on the blood coagulation system is not fully understood. Here, we use computational modeling to test the hypothesis that acidosis delays and re...

BACKGROUND Tubulointerstitial fibrosis contributes to the progression of many forms of glomerular disease and to end-stage renal failure. Inflammatory mediators generated during glomerular injury may induce tubulointerstitial lesions by stimulating tubular cells. Thrombin has multiple biological functions in addition to its role in haemostasis and has been detected in the urine of patients with...

Human a-thrombin was modified by four different procedures to identify specific active site regions required for receptor binding and stimulation of cell division. Conjugation of a-thrombin with diisopropylphosphofluoridate (DIP-F) or methylsulfonyl fluoride (MS-F) yielded catalytically inactivated preparations. Nitration or limited proteolysis of a-thrombin led to nitro-a-thrombin or y-thrombi...

Blood vessels respond to injury by initiating cell proliferation and migration that result in vascular lesion formation. To determine the roles of thrombin and the thrombin receptor in this process, we characterized thrombin receptor expression in normal and injured arteries, thrombin receptor-mediated smooth muscle cell mitogenesis, and the regulation of thrombin receptor mRNA expression in vi...

Glycoprotein (GP) V is a major substrate cleaved by the protease thrombin during thrombin-induced platelet activation. Previous analysis of platelets from GP V-null mice suggested a role for GP V as a negative modulator of platelet activation by thrombin. We now report the mechanism by which thrombin activates GP V -/- platelets. We show that proteolytically inactive forms of thrombin induce ro...

A novel thrombin inhibitor based on single-stranded (ss) deoxynucleotides with the sequence GGTTGGTGTGGTTGG (thrombin aptamer) has been recently discovered. In this study, we tested its efficacy in inhibiting clot-bound thrombin activity and platelet thrombus formation in an ex vivo whole artery angioplasty model. The thrombin aptamer showed a specific dose-dependent inhibition of thrombin-indu...

OBJECTIVE Feedback activation of factor XI by thrombin is a likely alternative for tissue factor-dependent propagation of thrombus formation. However, the hypothesis that thrombin can initiate and propagate its formation in a factor XI-dependent and platelet-dependent manner has not been tested in a plasma milieu. METHODS AND RESULTS We investigated thrombin generation in recalcified platelet...

A new approach to on-resin detection of three model proteases (trypsin, chymotrypsin, and thrombin) has been developed, while at the same time already described methodology for simultaneous two enzymes (trypsin chymotrypsin) additionally generalized. Appropriate immobilized substrates, comprising specifically cleavable peptide sequences capped with fluorescent dyes, have synthesized on Rink Ami...

Background: Recombinant insulin glargine, a long-acting analogue of insulin, is expressed as proinsulin in host cell and after purification and refolding steps cleaved to active insulin by enzymatic digestion using trypsin and carboxypeptidase B. Since the proinsulin's B and C chains have several internal arginine and lysine residues, a number of impurities are generated following treatment wit...