Description: Sirtuin 1 (193-741) active enzyme. Sirtuin 1 is a NAD-dependent deacetylase, which regulates processes such as apoptosis and muscle differentiation by deacetylating key proteins. Deacetylates Lys-382 of p53/TP53 and impairs its ability to induce proapoptotic program and modulate cell senescence. Deacetylates TAF1B and thereby represses rDNA transcription by the RNA polymerase I. Involved in HES1- and HEY2-mediated transcriptional repression. Inhibits skeletal muscle differentiation by deacetylating PCAF and MYOD1. May serve as a sensor of the cytosolic ratio of NAD(+)/NADH, which is essential in skeletal muscle cell differentiation. Despite some ability to deacetylate histones in vitro, such activity is either weak or inexistent in vivo. Inhibited by nicotinamide. Activated by resveratrol (3,5,4-trihydroxy-trans-stilbene), butein (3,4,2,4- tetrahydroxychalcone), piceatannol (3,5,3,4-tetrahydroxy-trans-stilbene),Isoliquiritigenin(4,2,4-trihydroxychalcone), fisetin (3,7,3,4-tetrahydroxyflavone) and quercetin (3,5,7,3,4- pentahydroxyfla.Ivone). 3
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