Abstract: Pyrophosphatase (PPase) from pork longissimus dorsi muscle was purified by ultracentrifugation, 50%－70% saturated ammonium sulfate fractionation, DEAE-52 anion-exchange chromatography. The purified enzyme with molecular mass of 72 kD ran as a single band on SDS-polyacrylamide gel. The optimum pH and temperature for the isolated PPase was 7.5 and 50 ℃, respectively. Mg2+ was necessary for PPase and the activity reached maximum at a concentration of 4.75 mmol/L. Na+ and K+ inhibited the enzyme activity and the inhibitory effect of Na+ was stronger than K+. The kinetic constant Km and Vmax using TSPP as substrate were determined as 0.36 mmol/L and 0.086μmol/(L·min), respectively.

Key words: pyrophosphatase, purification, characterization, pork