Cho S W, Lee J, Choi S Y
Department of Biochemistry, College of Medicine, University of Ulsan, Seoul, Korea.
Eur J Biochem. 1995 Oct 1;233(1):340-6. doi: 10.1111/j.1432-1033.1995.340_1.x.
Two soluble forms of novel glutamate dehydrogenase isoproteins, designated GDH I and GDH II, have been purified from bovine brain. GDH I and GDH II were separated on a hydroxyapatite column and eluted by a step gradient at different phosphate concentrations (30 mM and 50 mM for GDH I and GDH II, respectively). The preparations were homogeneous on SDS/PAGE. GDH I and GDH II showed similarity in their molecular sizes and are composed of six identical subunits having a molecular size of 57,500 Da. Differences between the biochemical properties of GDH I and GDH II, such as N-terminal amino acid sequences of intact and tryptic-digested enzymes, kinetic parameters, optimum pH and heat stability, were extensively examined in both reductive amination of alpha-oxoglutarate and oxidative deamination of glutamate. The different effects of ADP on GDH isoproteins were also studied under various conditions. These results indicate that GDH I and GDH II, isolated from bovine brain, are novel and distinct polypeptides.
已从牛脑中纯化出两种新型谷氨酸脱氢酶同工蛋白的可溶性形式，分别命名为GDH I和GDH II。GDH I和GDH II在羟基磷灰石柱上分离，并通过不同磷酸盐浓度（分别为30 mM和50 mM的GDH I和GDH II）的分步梯度洗脱。这些制剂在SDS/PAGE上呈均一性。GDH I和GDH II在分子大小上相似，均由六个相同的亚基组成，每个亚基的分子大小为57,500 Da。在α-酮戊二酸的还原胺化和谷氨酸的氧化脱氨过程中，对GDH I和GDH II的生化特性差异进行了广泛研究，如完整酶和胰蛋白酶消化酶的N端氨基酸序列、动力学参数、最适pH和热稳定性。还在各种条件下研究了ADP对GDH同工蛋白的不同影响。这些结果表明，从牛脑中分离出的GDH I和GDH II是新型且不同的多肽。
