Ike J, Sangan P, Gunasekaran M
Department of Biology, Fisk University, Nashville, Tennessee 37208.
Microbios. 1992;69(279):119-27.
The lactate dehydrogenase (LDH) from Nocardia asteroides was purified to homogeneity by ammonium sulphate precipitation, gel filtration on Sephadex G-150 and DEAE-Sepharose column chromatography. The purified enzyme showed a single band in native condition which indicated its homogeneity. SDS-PAGE of the purified enzyme showed the presence of three bands which correspond to molecular weights of 60, 66 and 74 kDa. The pH and temperature optima of the purified enzyme were 9.5 and 50 degrees C, respectively. The metal ions Mn++, Fe++, Co++, Mg++ and Ca++, increased the purified LDH activity. On the other hand, enzyme activity was completely inhibited by CuCl2. Potassium chloride, ammonium sulphate and sodium chloride did not alter the enzyme activity. The purified enzyme exhibited a Km value of 1.6 x 10(-5) M for pyruvate.
通过硫酸铵沉淀、Sephadex G - 150凝胶过滤和DEAE - Sepharose柱色谱法，将星形诺卡氏菌的乳酸脱氢酶（LDH）纯化至同质。纯化后的酶在天然状态下呈现单一条带，表明其均一性。纯化酶的SDS - PAGE显示存在三条带，分别对应分子量为60、66和74 kDa。纯化酶的最适pH和温度分别为9.5和50℃。金属离子Mn++、Fe++、Co++、Mg++和Ca++可提高纯化的LDH活性。另一方面，CuCl2完全抑制酶活性。氯化钾、硫酸铵和氯化钠不改变酶活性。纯化酶对丙酮酸的Km值为1.6×10(-5) M。
