Albertyn J, van Tonder A, Prior B A
Department of Microbiology and Biochemistry, University of the Orange Free State, Bloemfontein, South Africa.
FEBS Lett. 1992 Aug 17;308(2):130-2. doi: 10.1016/0014-5793(92)81259-o.
The NAD-dependent glycerol-3-phosphate dehydrogenase (glycerol-3-phosphate:NAD+ oxidoreductase; EC 1.1.1.8; G3P DHG) was purified 178-fold to homogeneity from Saccharomyces cerevisiae strain H44-3D by affinity- and ion-exchange chromatography. SDS-PAGE indicated that the enzyme had a molecular mass of approximately 42,000 (+/- 1,000) whereas a molecular mass of 68,000 was observed using gel filtration, implying that the enzyme may exist as a dimer. The pH optimum for the reduction of dihydroxyacetone phosphate (DHAP) was 7.6 and the enzyme had a pI of 7.4. NADPH will not substitute for NADH as coenzyme in the reduction of DHAP. The oxidation of glycerol-3-phosphate (G3P) occurs at 3% of the rate of DHAP reduction at pH 7.0. Apparent Km values obtained were 0.023 and 0.54 mM for NADH and DHAP, respectively. NAD, fructose-1,6-bisphosphate (FBP), ATP and ADP inhibited G3P DHG activity. Ki values obtained for NAD with NADH as variable substrate and FBP with DHAP as variable substrate were 0.93 and 4.8 mM, respectively.
通过亲和色谱和离子交换色谱从酿酒酵母菌株H44-3D中纯化出依赖NAD的甘油-3-磷酸脱氢酶（甘油-3-磷酸：NAD+氧化还原酶；EC 1.1.1.8；G3P DHG），纯化倍数达178倍，达到同质。SDS-PAGE表明该酶的分子量约为42,000（±1,000），而使用凝胶过滤法观察到的分子量为68,000，这意味着该酶可能以二聚体形式存在。还原磷酸二羟丙酮（DHAP）的最适pH为7.6，该酶的pI为7.4。在还原DHAP时，NADPH不能替代NADH作为辅酶。在pH 7.0时，甘油-3-磷酸（G3P）的氧化速率为DHAP还原速率的3%。测得NADH和DHAP的表观Km值分别为0.023和0.54 mM。NAD、果糖-1,6-二磷酸（FBP）、ATP和ADP抑制G3P DHG活性。以NADH为可变底物时NAD的Ki值和以DHAP为可变底物时FBP的Ki值分别为0.93和4.8 mM。
Zotero 插件