Acetylation regulates the amount of metabolic enzymes. Acetylation can regulate the steady-state levels of metabolic enzymes by promoting their degradation through either the ubiquitin–proteasomal system in the case of phosphoenolpyruvate carboxykinase (PCK1; A) or CMA in the case of PK M2 isoform (PKM2; B). Metabolic enzymes and acetylated lysine residues (K) are colored in light green and purple, respectively. Active sites are indicated by three red radial dashes.