Acid phosphatase of the prostatic gland. I. Isolation and purification; enzymatic kinetics

Abstract

Study of the acid phosphatases of the prostate gland. — I. Isolation and purifying; enzymatic kinetic

By employing a fractionation method in coluros of DEAE-cellulose, a fraction has been isolated with acid phosphatase activity in normal human prostates, while the glands which present hypertrophy show two of these fractions. Of these, one is shown quantitatively with very few variations, and presents the same characteristics as the enzymatic componet of the nor­mal prostate; while the second presents a different behaviour in the fractionation process and is shown quantitatively to a value which keeps a direct relation to the degree of hypertrophy.

Highly purified preparations have been obtenained of acid phosphatase tied to the degree of glandular hypertrophy (frac­tion I), which has permitted the study of its physical-chemical characteristics and their comparison with those of the normal enzymatic fraction (fraction II).

We have found the isoelectric pH va­lues of 5.4 and 4.6 for fractions I and II respectively, with an electrophoretic mobility corresponding to the zone between the albumins and serie alphaj-globulins for the second, and between the beta-globulins and gamma-globulins for the first.

For fraction I we have found an optimum activity pH of 5.4 with p-nitro-phenyl-phosphate, and of 5.2-5.5 with phenyl-phosphate. For fraction II these values are, respectively, of 4.2-4.6 and 4.4-4.8. With tetracolamin-phenolphtalein-disphosphate the optimum zone is very little marked.

The studies of enzymatic kinetic indicate that p-nitrophenyl-phosphate has an inhibiting action at high concentrations. The use of lower concentrations has allowed the calculation of the Michaelis’s constants: 1.01 X 10"4 M for fraction I, and 1.05 X 10-3 M for fraction H.