Purification and Characterization of an Acid Phosphatase from Mycoplasma fermentans

An acid phosphatase associated with the cell membranes of Mycoplasma fermentans was released from the membranes with Triton X-100, then purified by ion-exchange chromatography on DEAE-Sephacel and CM-Sepharose, followed by affinity chromatography on Con A-Sepharose. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme revealed a single band with a molecular mass of 31.2 kilodaltons. The enzyme activity toward p-nitrophenyl phosphate was enhanced remarkably by Cu²⁺, Co²⁺ and Mg²+, but the activity was not inhibited by EDTA. The enzyme dephosphorylated 0-phospho-L-tyrosine as well as p-nitrophenyl phosphate, but not O-phospho-L-threonine, O-phospho-L-serine, glucose-l-phosphate, phosphoryl choline and adenosine triphosphate. The level of the 0-phospho-L-tyrosine phosphatase activity was the highest in Mycoplasma faucium and the second highest in Mycoplasma fermentans of all tested human mycoplasmas.