Sirtuins (silent information regulator 2 [Sir2] proteins) belong to an ancient family of
evolutionary conserved nicotinamide adenine dinucleotide (NAD)+-dependent enzymes
with deacetylase and/or mono-ADP-ribosyltransferase activity. They regulate DNA repair
and recombination, chromosomal stability, and gene transcription, and most importantly
mediate the health-promoting effects of caloric restriction (CR), which includes the
retardation of aging. At least seven Sir2 homologs, sirtuins (SIRT) 1 to 7 have been identified …