A QUANTITATIVE STUDY OF THE PHOSPHATASE ACTIVITY OF MICROCOCCUS PYOGENES

Abstract

Using p-nitrophenyl phosphate disodium as a substrate, and a colorimet-ric method adapted from the technique used for serum phosphatase determination, a substrate concentration of 1 g/1 gives 95.9% of the theoretical maximum phosphomonoesterase activity. A cell concentration of 108/ml is minimal for detectable activity. Enzymatic hydrolysis is a linear function of cell concentration and of time (measured for 5 hours). pH Dependence is critical as indicated by a 40 to 70% reduction in activity with a change of 1.5 pH units from the optimum at pH 5.6. A minimum cell concentration of 50 x 108/ml is recommended for routine determinations, using a substrate concentration of 1''g/1 for 30 minutes.