In enzymology, an acyloxyacyl hydrolase (EC 3.1.1.77) is an enzyme that catalyzes the chemical reaction In enzymology, an acyloxyacyl hydrolase (EC 3.1.1.77) is an enzyme that catalyzes the chemical reaction Hence, this enzyme has one substrate, the 3-(acyloxy)acyl groups of bacterial lipopolysaccharides, and two products, and fatty acid.