Figure 4.
Relationship between co-enzymes and reversible acetylation. coA, which is synthesized from pantothenate in cytoplasm and mitochondria (not shown) is ultimately imported into mitochondria, where it becomes acetylated by pyruvate and fatty acid oxidation and amino acid catabolism. Protein acetylation releases free coA. Mitochondrial protein deacetylation depends on NAD+ and Sirt3, producing nicotinamide (Nam) and Ac- ADPribose (not shown) in addition to nonmodified protein. Salvage to nicotinamide mononucleotide (NMN) occurs in the cytoplasm as a function of Nam and Nam phosphoribosyltransferase (Nampt) or nicotinamide riboside (NR) and nicotinamide riboside kinase (Nrk). NMN is imported to mitochondria, where it is a substrate of NMN adenylytransferase 3 (Nmnat3).