Sirtuins are phylogenetically conserved from bacteria to humans and regulate cell functions beyond silencing. The proteins show a relevance to cancer, obesity, muscle differentiation, inflammation and neurodegeneration. In addition, Sirtuin activity may extend the lifespan of several organisms.
Human Sirtuins (class III protein deacetylases) utilize NAD+ as cosubstrate and act either as deacetylases or as ADP-ribosyltransferases.
Figure: Crystal structure of human Sirt5 in complex with an inhibitor