Enzymatic dephosphorylation of 3'-phosphoadenosine 5'-phosphosulfate to adenosine 5'-phosphosulfate in sheep brain

Abstract

An enzyme catalyzing the dephosphorylation of 3'-phosphoadenosine 5'-phospho[³⁵S]sulfate to adenosine 5'-phospho[³⁵S]sulfate was partially purified from sheep brain. The enzyme showed an optimum pH of 5.0; it was activated by EDTA and inhibited by the divalent metal ions tested. ADP and 3'-AMP had no significant influence on the enzyme activity, but 3'-phosphoadenosine 5'-phosphate was a potent inhibitor. NaF completely inhibited the reaction. The enzyme exhibited properties much different from those 3'-nucleotidase and 3'-phosphoadenosine 5'-phosphosulfate sulfohydrolase of brain. The physiological role of the phosphohydrolase may be in the regulation of the concentration of 3'-phosphoadenosine 5'-phosphosulfate.