OAADPR

OAADPR stands for O-acetyl-ADP-ribose, a nucleotide-like metabolite produced during NAD+-dependent deacetylation reactions catalyzed by sirtuin enzymes. In the sirtuin reaction, an acetylated lysine residue is deacetylated, with NAD+ consumed and nicotinamide released; the reaction yields OAADPR as a byproduct. OAADPR is structurally ADP-ribose bearing an acetyl group on the ribose moiety, hence its name.

Biological context and potential roles: OAADPR has been studied as a potential signaling molecule in cellular metabolism and calcium signaling. Some research has proposed that OAADPR can modulate calcium channels, such as the TRPM2 channel, or influence other signaling pathways, though its exact physiological role remains context-dependent and debated. The compound is often used as a biochemical indicator of sirtuin activity, with cellular OAADPR levels reflecting NAD+-dependent deacetylation processes.

Occurrence and metabolism: OAADPR has been detected in various organisms, including mammals, and its cellular abundance can vary with metabolic state, NAD+ availability, and sirtuin expression. Enzymes described as OAADPR hydrolases or related pyrophosphatases can further metabolize OAADPR into other nucleotide or sugar derivatives, linking it to broader energy and nucleotide metabolism pathways.

Nomenclature and research status: OAADPR is also referred to as O-acetyl-ADP-ribose, with abbreviations including OAADPr or OAADPR in different sources. Its functional significance is an active area of research, with ongoing work to clarify when and how OAADPR influences cellular signaling versus serving primarily as a byproduct of sirtuin-catalyzed reactions.