SIRT5 belongs to the Sirtuin family of proteins, homologs to the yeast Sir2 protein. Sirtuin family members hold a sirtuin core domain and grouped into four classes. The protein encoded by this gene is included in class III of the sirtuin family. Human sirtuins functions were not yet determined; still, yeast sirtuin proteins are known to regulate epigenetic gene silencing and suppress recombination of rDNA. Studies propose that human sirtuin could operate as intracellular regulatory protein with mono-ADP-ribosyltransferase activity. SIRT5 Human Recombinant produced in E.Coli is a single, non-glycosylated polypeptide chain topological domain containing 300 amino acids (34-310 a.a) and having a molecular mass of 32.5kDa. SIRT5 is fused to a 23 amino acid His-tag at N-terminus & purified by proprietary chromatographic techniques.