Purification and properties of glutamate-phenylpyruvate aminotransferase from rumen bacterium Prevotella albensis

Glutamate-phenylpyruvate aminotransferase (GPAase) from a cell free extract of a rumen bacterium Prevotella albensis was purified 36-folds. The molecular weight of the GPAase was estimated to be 39.0 kDa by SDS-PAGE. The optimum pH of GPAase was 6.2 and the activity declined markedly above pH 8.5. GPAase was reactive over a wide range from pH 4.5 to 10.5. The maximum reaction velocity of GPAase was observed at a temperature of 50°C and at higher temperatures over 60°C, the activity declined. The GPAase was stable below 60°C. Most of the chemical agents and metal ions showed inhibition effects on GPAase activity.