猪肝L—岩藻糖脱氢酶的纯化及性质研究

Studies on Purification and Characterization of L-Fucose Dehydrogenase from Pork Liver

猪肝匀浆液经硫酸铵分级沉淀、DEAE纤维素柱层析、SephadexG-100凝胶过滤得到以NAD+为辅酶的L-岩藻糖脱氢酶,其纯化倍数和收得率分别为229.5%和40%.该酶的分子量为96500,与L-岩藻糖反应的km值为3.1×10-4mol/L,NAD+的km值为2.1×10-5mol/L,最适pH值为8.6,对D-阿拉伯糖、L-半乳糖、L-木糖和D-来苏糖有一定催化活力,但对后三者活力弱.

A NAD+-dependent L-fucose dehydrogenase is isolated from a pork liver extract and purified 229.5-fold with a yield of 40%.The purification produres included treatment with ammonium sulfate fractionation,DEAE chromatography,gelfiltration on sephadex G-100 .The enzyme has a molecular weight of about 96 500 and the optimum pH is at 8.6 ,with km values of 3.1×10-4 mol/L,2.1×10-5 mol/L for L-fucose and NAD+,respectively.The enzyme also catalyzed the oxidation of D-arabinose ,L-galactose,D-lyxose and L-xylose,but the last three sugars are much less effective substrate for the enzyme that L-fucose.