Figure 6.

Net acetylation during macronutrient overnutrition and macronutrient undernutrition. As depicted in Figures 2 and 5, overnutrition and undernutrition can produce high mitochondrial Ac-coA and protein acetylation of susceptible Lys residues. In this schematic, two of four Lys residues have depressed pK_a values, depicted as K: to represent the lone electron pair of a susceptible amino group. Two Lys residues without perturbed pK_a values and an Arg are depicted as positively charged. One susceptible Lys is on an α-helix, one turn away from Arg. The other susceptible Lys is buried and partially desolvated. Under conditions of overnutrition, Sirt3 expression declines, such that both classes of acetylation are sustained. Under conditions of undernutrition, Sirt3 expression increases, leading to deacetylation of the exposed but not the buried Lys residue.