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Partial Characterization of an Acidic Protease from Rhizopus stolonifer RN-11
Abstract
The present study characterises an acidic protease purified from the Rhizopus stolonifer strain, RN-11. The acidic protease with a 70 kDa molecular weight, was stable within pH 2-4 at temperatures 40-50°C. The temperature and pH value conducive to optimal catalytic activity were pH 2.5 and 50°C, respectively. Treatment with 5 mmol metal ions showed that the acidic protease was activated by Na+, K+, Mn2+, Cu2+ and Ca2+, inhibited by Zn2+, Li2+ and Fe2+, and unaffected by Mg2+. It was proposed that the studied acidic protease might represent a previously uncharacterised type of acidic protease produced by the Rhizopus stolonifer RN-11 strain.