Anion and divalent cation activation of phosphoglycolate phosphatase from leaves

Phosphoglycolate (P-glycolate) phosphatase was purified 223-fold from spinach leaves by (NH4)2SO4 fractionation, DEAE-cellulose chromatography, and Sephadex G-200 chromatography. The partially purified enzyme had a broad pH optimum between 5.6 and 8.0 and was specific for the hydrolysis of P-glycolate with a Km (P-glycolate) of 26 microM. The enzyme was activated by divalent cations including Mg2+, Co2+, Mn2+, and Zn2+, and by anions including Cl-, Br-, NO-3, and HCOO-. Neither anions nor divalent cations activated the enzyme without the other. The P-glycolate phosphatase activities from tobacco leaves or the green algae, Chlamydomonas reinhardtii, also required Mg2+ and were activated by chloride. In addition, the enzyme was allosterically inhibited by ribose 5-phosphate. The activation of P-glycolate phosphatase by both anions and divalent cations and the inhibition by ribose 5-phosphate may be involved in the in vivo regulation of P-glycolate phosphatase activity.