HISTOCHEMICAL AND BIOCHEMICAL-STUDIES OF THE KINETICS OF NONSPECIFIC ACID-PHOSPHATASE IN RAT-KIDNEY

Kinetic characteristics of non-specific acid phosphatase (orthophospho ric monoester phosphohydrolase, E.C.3.1.3.2.) from rat kidney were det ermined fluorometrically using 4-methylumbelliferyl phosphate as the s ubstrate. Kinetic characteristics measured by similar methods both his tochemically in cryostat sections and biochemically in tissue extracts were compared. Histochemical and biochemical methods gave essentially similar results in respect of Michaelis-Menten constants (K(m)), pH o ptima, effect of fluoride inhibition and the effect of changes in incu bation temperatures in the range 10-degrees-C to 37-degrees-C. This co nfirms the validity of both methods, and also gives greater confidence that the enzyme in vitro closely approximates the properties of the e nzyme as it functions in vivo.