Dr Daniel J. Guerra of Authentic Biochemistry lectures on Senescence in Human Aging: The Sirtuin Intrusion

Sirtuins are protein deacetylases with multiple isoforms active in the nucleus, cytosol and mitochondria all serving unique functions and requiring NAD+. These sirtuins function to condense chromatin and yet  protein abundance has less to do with potency than does the availability of NAD+ which can be synthesized from multiple routes. Furthermore, SIRT1 has been associated with  antagonizing age-related decreases in the amplitudes of the SCN output obtaining age-linked differentiating  phases of increases and decreases observed within a circadian cycle..

References:

Int J Mol Sci. 2019 Mar; 20(5): 1223.

PLOS One November 25, 2014 https://doi.org/10.1371/journal.pone.0113939

Circ Res. 2018 Sep 14; 123(7): 868–885