Purification and Properties of the Acidic N-acetyl-β-D-glucosaminidase from Porcine Semen

The acidic N-acetyl-β-D-glucosaminidase (EC3.2.1.52) was purified from the porcine semen by ammonium sulfate fractionation,chromatography on DEAE-32 and Sephadex G-100. The specific activity of the enzyme was 1 773.25 U mg-1. The purified enzyme preparation was homogeneous judged by polyacrylamide gel electrophoresis. The molecular weights of two subunits of the purified enzyme were determined to be 129.13×103 and 62.24×103,respectively. The pI value was calculated to be 5.10 by isoelectric focusing. The optimum temperature and pH of the enzyme were 60 ℃ and 5.5. The enzyme was stable in the pH ranges from 3.6 to 9.2 under 37 ℃ and at temperature ranges from 10 to 55 ℃. The Km and Vm values were determined to be 0.455 mmol/L and 17.34 μmol L-1 min-1 at pH 5.6 and at 37 ℃,respectively. The activation energy of the enzyme for hydrolysis of the substrate was 41.70 kJ mol-1. Fig 8,Tab 1,Ref 15