Purification and properties of phosphoserine aminotransferase from bovine liver

Abstract l -Phosphoserine aminotransferase was purified from bovine liver to apparent homogeneity as judged by nondenaturing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, analytical ultracentrifugation, and immunochemical analysis. The purification procedure described involves the specific elution of the enzyme from Cibacron blue-agarose by micromolar concentrations of its substrate, phosphohydroxypyruvate. The purified enzyme had a specific activity of approximately 13 μmol of phosphohydroxypyruvate formed min −1 mg −1 of protein at 38 °C. Determinations of the native molecular weight and the subunit molecular weight indicated that the phosphoserine aminotransferase from bovine liver was a dimer composed of two subunits with identical molecular Weights of 43,000.