sentences:  Through hydrogen bonds with Ser16 and Met210, Lys116 positions Lys115 in the hydrophobic pocket of the active site to favor the neutral amine form.Acetoacetate decarboxylase from "Clostridium acetobutylicum" catalyzes the decarboxylation of acetoacetate to yield acetone and carbon dioxide (Figure 1).The reaction mechanism proceeds via the formation of a Schiff base intermediate, which is covalently attached to lysine 115 in the active site.