Abstract
The presence of a Zn2+-dependent acid p-nitrophenyl phosphatase (EC 3.1.3.2) in bovine liver was described. The enzyme was purified to apparent homogeneity and migrates as a single band during electrophoresis on polyacrylamide gel. The enzyme requires Zn2+ ions for catalytic activity, other bivalent cations have little or no effect. The enzyme, of Mr 118,000, optimum pH 6-6.2 and pI 7.4-7.5, was inhibited by EDTA, tartrate, adenine and ATP, but not by fluoride. The common phosphate esters are poor substrates for the enzyme, which hydrolyses preferentially p-nitrophenyl phosphate and o-carboxyphenyl phosphate. The Zn2+-dependent acid p-nitrophenyl phosphatase of bovine liver was different from the high-Mr acid phosphatases previously detected in mammalian tissues.