Protein lysine acetylation is carried out by either enzymatic or chemical mechanism in <i>B</i>. <i>subtilis</i>.

A model of enzymatic and chemical acetylations on the lysine residues of a putative protein substrate. For the enzymatic mechanism, an acetyltransferase (AcuA in B. subtilis) takes the acetyl group (Ac) from a donor such as acetyl-CoA and adds it to a lysine residue on a target protein. This reaction can be reversed by the activity of a deacetyltransferase (AcuC or SrtN in B. subtilis). Chemical acetylation uses acetyl-phosphate, an intermediate in the acetate metabolic pathway, as the donor of the acetyl group to directly acetylate lysine residues of the target protein. “+” represents the positively charged lysine residue on the target protein. Pdh, pyruvate dehydrogenase; Pta, phosphotransacetylase; AckA, acetate kinase; AcsA, acetyl-CoA synthetase.