Coenzymes are derived from several members of a special class of nutrients known as vitamins. For example, the coenzyme NAD+ (nicotinamide adenine dinucleotide) is derived from the B-vitamins niacin. As we will see, it plays major role in energy metabolism by transferring hydrogen from one substrate to another.
Widmaier, E.P., & Raff, H. (2008). Vander’s Human Physiology: The Mechanisms of Body Function. New York, NY: McGraw-Hill.
NAD+ is a cosubstrate for other enzymes such as the sirtuins and poly(adenosine diphosphate–ribose) polymerases. Cellular NAD+ concentrations change during aging, and modulation (調整) of NAD+ usage or production can prolong both health span and life span. Here we review factors that regulate NAD+ and discuss how supplementation with NAD+ precursors may represent a new therapeutic opportunity for aging and its associated disorders, particularly neurodegenerative diseases.
Verdin, E. (2015). NAD+ in aging, metabolism, and neurodegeneration. American Association for the Advancement of Science, 350(6265), 1208-1213.
Sirtuins are a conserved family of proteins found in all domains of life. The first known sirtuin, Sir2, regulates ribosomal DNA recombination, gene silencing, DNA repair, chromosomal stability and longevity. Sir2 homologues (同系物) also modulate lifespan in worms and flies, and may underlie (構成…的基礎) the beneficial effects of caloric restriction, the only regimen that slows aging and extends lifespan of most classes of organism, including mammals. Sirtuins have gained considerable attention for their impact on mammalian physiology, since they may provide novel targets for treating diseases associated with aging and perhaps extend human lifespan. In this review we describe our current understanding of the biological function of the seven mammalian sirtuins, SIRT1–7, and we will also discuss their potential as mediators of caloric restriction and as pharmacological targets to delay and treat human age-related diseases.
Michan, S., & Sinclair, D. (2007). Sirtuins in mammals: insights into their biological function. Biochemical Journal, 404(1), 1–13.
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