Sirt5 deacylation activities show differential sensitivities to nicotinamide inhibition.

ABSTRACT: Sirtuins are protein deacylases regulating metabolism and aging processes, and the seven human isoforms are considered attractive therapeutic targets. Sirtuins transfer acyl groups from lysine sidechains to ADP-ribose, formed from the cosubstrate NAD(+) by release of nicotinamide, which in turn is assumed to be a general Sirtuin inhibitor. Studies on Sirtuin regulation have been hampered, however, by shortcomings of available assays. Here, we describe a mass spectrometry-based, quantitative deacylation assay not requiring any substrate labeling. Using this assay, we show that the deacetylation activity of human Sirt5 features an unusual insensitivity to nicotinamide inhibition. In contrast, we find similar values for Sirt5 and Sirt3 for the intrinsic NAD(+) affinity as well as the apparent

SUBMITTER: Fischer F 

PROVIDER: S-EPMC3446968 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature