[Proteolytic resistance and thermostability of catalase and histidine decarboxylase from Micrococcus sp. n]

Catalase from Micrococcus sp. n. is not hydrolyzed by trypsin at the protein/protease (pn/pe) exceeding 10/1. Histidine decarboxylase (HDC) loses 50% of activity after the first nine minutes of hydrolysis at the pn/pe ratio equal to 6/1, followed by a slow linear inactivation. Investigation of thermal stability at varying pH and temperatures demonstrated that catalase and HDC preserve 70-80% of activity after 5 minutes of incubation at 72 degrees C only at pH approaching the optimal pH of enzymatic activity (pH 7.45 for catalase and pH 5.55 for HDC).