Purification and stability of an antithrombus enzyme from Bacillus subtilis

An antithrombus enzyme (ATE) was precipitated by (NH4)(2)SO4 or ethanol from supernatant of Bacillus subtilis culture broth then purified using ion exchange chromatography on CM-sepharose fast flow. The effects of ionic strength and pH value on protein adsorption, the gradient elution at different flow rates and step elution were examined respectively. The recovery yield of the optimised process was 74.5% with a purification factor 8.1. The ATE molecular weight was estimated as 30ku by SDS-PAGE. The experimental results showed that the enzyme was stable in the range of pH 7 to pH11, and temperature 25degreesC to 37degreesC.