Han M K, Lee J Y, Cho Y S, Song Y M, An N H, Kim H R, Kim U H
Department of Biochemistry, Chonbuk National University Medical School, Chonju, Korea.
Biochem J. 1996 Sep 15;318 ( Pt 3)(Pt 3):903-8. doi: 10.1042/bj3180903.
NAD+ glycohydrolase (NADase; EC 3.2.2.5) is an enzyme that catalyses hydrolysis of NAD+ to produce ADP-ribose and nicotinamide. Its physiological role and the regulation of its enzymic activity have not been fully elucidated. In the present study, the mechanism of self-inactivation of NADase by its substrate, NAD+, was investigated by using intact rabbit erythrocytes and purified NADase. Our results suggest that inactivation of NADase was due an auto-ADP-ribosylation reaction. ADP-ribosylated NADase of rabbit erythrocytes was deADP-ribosylated when incubated without NAD+, and thus enzyme activity was simultaneously restored. These findings suggest that reversible auto-ADP-ribosylation of NADase might regulate the enzyme's activity in vivo.
NAD+糖水解酶(NADase;EC 3.2.2.5)是一种催化NAD+水解生成ADP-核糖和烟酰胺的酶。其生理作用及其酶活性的调节尚未完全阐明。在本研究中,通过使用完整的兔红细胞和纯化的NADase,研究了NADase被其底物NAD+自失活的机制。我们的结果表明,NADase的失活是由于自动ADP-核糖基化反应。兔红细胞的ADP-核糖基化NADase在无NAD+的情况下孵育时会发生去ADP-核糖基化,因此酶活性同时恢复。这些发现表明,NADase的可逆自动ADP-核糖基化可能在体内调节该酶的活性。