日本沼虾(Macrobrachium nipponense)N-乙酰－β-D-氨基葡萄糖苷酶初步纯化及部分性质

A β-N-Acetyl-D-glucosaminidase (EC3.2. 1.30, NAGase) was purified from the viscera of Macrobrachium nipponense by ammonium sulfate fractionation, chromatography on DEAE-32 and Sephadex G-100. The specific activity of the enzyme was 3 000 U mg-. The optimum pH and temperature were determined to be at pH 6.0 and 53℃, respectively. The enzyme was stable at pH ranging from 4.5 to 9.3 under 37℃, which was followed by typical Michaelis-Menten kinetics for the hydrolysis of pNP-β-D-G1cNAc. The K(subscript m) and V(subscript m) values were determined to be 0.165 mmol L^(-1) and 6.554 μmol L^(-1) min^(-1) respectively. The activation energy of the enzyme for the hydrolysis of pNP-β-D-G1cNAc was detemined to be 63.55 kJ mol^(-1).