Thrombin group properties

The phospholipase As from Vinera Berus venom was purified and its properties were determined77 (mol. wt. 13,400 and isoelectric point 9.2). This enzyme hydrolyses the acyl group at the 2 position of phospholipid, thereby reducing the procoagulant activity of the phospholipoprotein cofactor in thrombin production. 

In recent years, a great deal of effort has been devoted to the study of antithrombogenic polymers (1-3).It has been shown in the present authors laboratory (4-7) that modified insoluble polystyrenes substituted either with sulfonate or amino acid sulfamide groups, exhibit anticoagulant activity, when suspended in plasma. This property can be attributed to the adsorption of thrombin and antithrombin III, at the plasma-polymer interfaces (7-9). 

Phaneuf et al. have developed a novel biomaterial surface that provides both localised infection resistance and haemostatic properties. Functional groups were created with woven Dacron material through exposure to ethylenediamine (C-EDA) and the antibiotic ciprofloxacin was then applied to the C-EDA using the pad/autoclave technique followed by surface immobilisation of the coagulation cascade enzyme thrombin. It was found that the antimicrobial activity of the treated fabric surface persisted for 5 days compared with the untreated fabric. Thrombin surfaces had 2.6-and 105-fold greater surface thrombin activity compared with non-specifically bound thrombin and ciprofloxacin-dyed surfaces, respectively. This study demonstrated that ciprofloxacin and thrombin can be simultaneously incorporated onto a biomaterial surface while maintaining their respective biological activities (Phaneuf et al., 2005). 

Fig. 17 Properties of a series of thrombin inhibitors the pifa of the amino group of the tricyclic skeleton (plfai), the piTa of the amidinium residue (pifa2), log D, binding affinity (Ki), and selectivity for thrombin compared to trypsin as a function of fluorine substitution [95]...

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