DEPHOSPHORYLATION OF ADENOSINETRIPHOSPHATE BY NORMAL AND PATHOLOGICAL HUMAN SERA 1

Abstract

The dephosphorylation of ATP by normal and pathologic human sera exhibits 2 pH optima at about 8.9 and 4.8. Hydrolysis of ATP at pH 8.9 is associated with the splitting of all 3 phosphate bonds of ATP. Dephosphorylation of ATP at pH 4.8 usually consists of splitting of the labile phosphate linkages, and the evidence suggests that this activity is not due to acid phosphatase. The presence of an "acid" adenylpyrophosphatase in serum, seminal fluid, and possibly other tissues is suggested though not established. The effects of substrate concn., Ca, Mg, F, Cn, and dialysis on the splitting of ATP by human serum are descr. The pH-activity curves for the dephosphorylation of ATP by several animal sera are given. A comparison of ATP dephosphorylation and phosphomonoesterase in a small group of normal and pathologic human sera was made. Elevated adenosinepo-lyphosphatase activity was frequently associated with liver disease and bony metastasis from prostatic carcinoma.