Martín M, de la Banda I G, Sabater B
Rev Esp Fisiol. 1976 Jun;32(2):131-6.
The activity of L-Alanine: 2-oxoglutarate aminotransferase (E.C. 2.6.1.2) has been studied in maize (Zea mays) embryo. Crude extracts were fractioned with ammoniun sulfate to obtain low activity preparations of other aminotransferases present in crude extracts. The enzyme shows normal hyperbolic saturation curves for the substrasts: Pyruvate (Km 1 mM), 2-oxoglutarate (Km 0.4 mM) and L-Glutamate (Km 0.07 mM). However, it shows complex kinetics properties for the substrate L-Alanine, giving sigmoid saturation curves for L-Alanine at low but not at high fixed 2-oxoglutarate concentrations. These last results point to a regulation of the of L-Alanine degradation, which takes place during the germination of maize. Together with L-Glutamate and L-Alanine, the enzyme only seems to use L-Serine and L-Cysteine and their cetoacids.
已对玉米（Zea mays）胚中的L-丙氨酸：2-氧代戊二酸转氨酶（E.C. 2.6.1.2）活性进行了研究。用硫酸铵对粗提取物进行分级分离，以获得粗提取物中存在的其他转氨酶的低活性制剂。该酶对底物丙酮酸（Km 1 mM）、2-氧代戊二酸（Km 0.4 mM）和L-谷氨酸（Km 0.07 mM）呈现正常的双曲线饱和曲线。然而，它对底物L-丙氨酸表现出复杂的动力学特性，在低但不是高固定2-氧代戊二酸浓度下，L-丙氨酸呈现S形饱和曲线。这些最新结果表明，在玉米萌发过程中发生了对L-丙氨酸降解的调节。该酶似乎仅与L-谷氨酸和L-丙氨酸一起使用L-丝氨酸和L-半胱氨酸及其酮酸。
