Alvarez-Gonzalez R, Moss J, Niedergang C, Althaus F R
Biomedical Division, Samuel Roberts Noble Foundation, Inc., Ardmore, Oklahoma 73402.
Biochemistry. 1988 Jul 12;27(14):5378-83. doi: 10.1021/bi00414a063.
A homogeneous preparation of an arginine-specific mono(ADP-ribosyl)transferase from turkey erythrocytes effectively utilized 2'-deoxy-NAD+ for the 2'-deoxy(ADP-ribose) modification of arginine methyl ester with an apparent Km of 27.2 microM and a Vmax of 36.4 mumol min-1 (mg of protein)-1. The adduct formed was also used as a substrate by an avian erythrocyte arginine(ADP-ribose)-specific hydrolase that generated free 2'-deoxy(ADP-ribose). In contrast, 2'-deoxy-NAD+ was not a substrate in the initiation or elongation reaction catalyzed by highly purified poly(ADP-ribose) polymerase from calf thymus. However, 2'-deoxy-NAD+ was a potent noncompetitive inhibitor of NAD+ in the elongation reaction catalyzed by the polymerase, with an apparent Ki of 32 microM. These results indicate that 2'-deoxy-NAD+ may be utilized to specifically identify protein acceptors for endogenous mono(ADP-ribosyl)transferases in complex biological systems that may contain a high activity of poly(ADP-ribose) polymerase, i.e., cell nuclei preparations.
从火鸡红细胞中提取的精氨酸特异性单（ADP-核糖基）转移酶的均一制剂，能有效地利用2'-脱氧-NAD+对精氨酸甲酯进行2'-脱氧（ADP-核糖）修饰，其表观Km为27.2微摩尔，Vmax为36.4微摩尔·分钟-1（毫克蛋白）-1。形成的加合物也可被禽红细胞精氨酸（ADP-核糖）特异性水解酶用作底物，该酶可生成游离的2'-脱氧（ADP-核糖）。相比之下，2'-脱氧-NAD+不是来自小牛胸腺的高度纯化的聚（ADP-核糖）聚合酶催化的起始或延伸反应的底物。然而，在该聚合酶催化的延伸反应中，2'-脱氧-NAD+是NAD+的有效非竞争性抑制剂，表观Ki为32微摩尔。这些结果表明，在可能含有高活性聚（ADP-核糖）聚合酶的复杂生物系统（即细胞核制剂）中，2'-脱氧-NAD+可用于特异性鉴定内源性单（ADP-核糖基）转移酶的蛋白质受体。
