In vitro studies on a novel micelle-forming peptide with anticoagulant activity

A novel peptide, tert-butyloxycarbonyl-L-arginine-L-proline lauryl ester laurate, synthesised by a solution-phase method, formed micelles in aqueous solutions and was observed to exhibit anticoagulant activity as shown by clotting assays such as the thrombin time (TT) test, the prothrombin time (PT) test and the activated partial thromboplastin time (APTT) test. TT and PT were found to be normal up to a particular concentration of peptide, and above that level they increased with increasing concentration of peptide, while APTT did not exhibit much significance. Conductometric and potentiometric studies showed that the peptide formed a stable micelle, and the anticoagulant activity of this peptide was also compared with a non-arginine-containing peptide (control) known to form micelles. The anticoagulant action in the micellar form could be due to the inhibition of thrombin, as seen from the decrease in amidolytic activity. The inhibitory activity of the peptide was explained in the light of micelle formation.