Mammalian Sirtuins SIRT4 and SIRT7

Sirtuins are a family of intracellular enzymes whose enzymatic activities include catalyzing the beta-nicotinamide adenine dinucleotide (beta-NAD(+))-dependent N-epsilon-acyl-lysine deacylation and the beta-NAD(+)-dependent mono-ADP-ribosylation. Among the seven sirtuin family members (i.e., SIRT1-7) thus far identified in mammals including humans, we know SIRT1/2/3/5/6 better than SIRT4/7 as for their enzymatic activities and the cellular roles of the reactions they catalyze. This chapter will provide an updated account on the enzymology and biology of SIRT4 and SIRT7, the two less well-understood mammalian sirtuins. It is hoped that this article will also be able to set a stage for the medicinal chemistry work on SIRT4 and SIRT7, potentially developing novel therapeutic agents for human diseases.