Isolation and characterization of alkaline phosphatase of Saccharopolyspora erythraea from fermentation broth of erythromycin production

Alkaline phosphatase having two pH optima (8.4 and 9.2) was excreted in substantial amount by Saccharopolyspora erythraea during erythromycin production and was precipitated from the broth with 60 80 % final saturation of ammonium sulphate. PAS and silver nitrate staining of SDS-gel electrophoresis depicted eight distinct bands of glycoproteins in the precipitate. Buffer A (pH 8.4) eluted the glycoproteins from native gels and showed four bands of phosphatase with optimum activity at pH 8.4 and four at pH 9.2. After three successive native gel electrophoreses and elutions, four isomers of pH 8.4 were isolated with Buffer A and four of pH 9.2 with Buffer B (pH 9.2). The eight isoenzymes of alkaline phosphatase were purified more than 20-folds and were characterized as glycoproteins of different molecular weights, turnover numbers and extensive sugar percentages in their molecules.