Improvement in Half-life of Streptokinase by PEGylation

Abstract

An extracellular protein secreted by various strains of Streptococci is known as streptokinase. It is used clinically as an intravenous thrombolytic agent for the treatment of acute myocardial infarction. With this view, the present study was undertaken, where 13 isolates of streptococci species were isolated from different samples like curd, faeces and milk. Out of which 9 isolates were gram-positive showing beta-haemolytic activity and were catalase negative. Screening for streptokinase activity was investigated using caseinolytic method, and these isolates showed positive proteolytic activity. Enzyme production was obtained using batch fermentation. Partial purification of enzyme was done by ammonium sulphate precipitation followed by dialysis. PEGylation of partially purified streptokinase enzyme was done successfully, and PEGylated streptokinase showed higher clot lysis compared to clot lysis by the native enzyme. Keywords: streptokinase, thrombolytic activity, blood clot lysis, conjugated-sk, pegylation