English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A number of studies have been reported in which the procoagulant activity of Echis carinatus venom (ECV) has been used to investigate the structure-function of human and bovine prothrombin (II). While it is clear that ECV activates II by cleaving between the A chain-B-chain of the thrombin region of the zymogen,, the literature is not clear on the activity of ECV in terms of cleaving at other sites. Specifically, one report suggested that ECV cleaves II between the Fragment 1 and prethrombin 1 regions (F 1-Pre 1) of the zymogen and that this cleavage is required for further cleavage and activation of II. Another report suggested that ECV does not cleave the F 1-Pre 1 bond at all. The ambiguity has arisen because of the well-known sensitivity of the F 1-Pre 1 bond to cleavage by thrombin and the inability of most thrombin inhibitors to block thrombin activity during the course of II activation by ECV. To this point, diisopropylphosphofluoridate, isoleucyl-pro-pyl-arginine chloromethyl ketone, and benzamidine did not prevent significant F 1-Pre 1 cleavage by ECV in the present study, Dansyl-arginine-N-(3-ethyl-l, 5-pentanediyl amide) (DAPA) however, appeared to afford nearly complete protection against F 1-Pre 1 cleavage during ECV activation of II. Since some F 1-Pre 1 cleavage was observed even in the presence of 10-3M DAPA (Ki = 10-7M) it appeared that ECV might cleave this bond at a relatively slow rate. This was confirmed by the results of experiments in which the rate of F 1-Pre 1 cleavage in the presence of DAPA was found to be proportional to the concentration of ECV. In addition, EDTA, which inhibits ECV activity, blocked further F 1-Pre 1 cleavage at a time when the conversion of prothrombin to meizothrombin was complete. Human prothrombin appeared to be much more susceptible to F 1-Pre 1 cleavage by ECV than bovine prothrombin. Our results suggest that the activation of prothrombin by ECV does not require F 1-Pre 1 cleavage by ECV as suggested by other investigators.

Cleavage Of Human Prothrombin By Partially Purified Echis Carinatus Venom