【摘要】 乳酸脱氢酶(LDH)是米根霉发酵生产L-乳酸中催化丙酮酸转化成L-乳酸过程的关键酶。本研究从米根霉As3.819中初步分离出乳酸脱氢酶,并结合发酵条件对其酶学特性进行了研究。结果表明,该乳酸脱氢酶的最适反应pH为7.4,最适催化温度为30～50℃。Mg2+、Ca2+对该酶有激活作用,K+、Zn2+对该酶有抑制作用。以NADH和丙酮酸为底物的米氏常数分别为7.22×10-4mol/L和1.24×10-3mol/L。更多还原

【Abstract】 Lactate Dehydrogenase (LDH) is a key enzyme which catalyzes the formation of lactic acid from pyruvic acid duringthe fermentation with Rhizopus oryzae. In this study, the crude LDH extract were obtained from mycelium of Rhizopus oryzaeAs3.819 and its properties were studied. The results show that LDH extract has optimum reaction pH of 7.4 and optimum catalysistemperature of 30～50℃. Mg2+ and Ca2+ increase the activity of LDH, but K+ and Zn2+ reduce its activity. The Km constants basedon the substrates of NADH and pyruvate are 7.22×10-4mol/L and 1.24×10-3mol/L respectively.更多还原