Galactoside acetyltransferase (also known as Galactoside O-acetyltransferase, thiogalactoside transacetylase, β-galactoside transacetylase and GAT) is an enzyme that transfers an acetyl group from acetyl-CoA to β-galactosides, glucosides and lactosides. It is coded for by the lacA gene of the lac operon in E. coli. Reaction It catalyzes the following reaction: acetyl-CoA + beta-D-galactoside → CoA + 6-acetyl-beta-D-galactoside The kinetics of the enzyme were delineated in 1995. Biological role The enzyme's role in the classical E.coli lac operon remains unclear. However, the enzyme's cellular role may be to detoxify non-metabolizable pyranosides by acetylating them and preventing their reentry into the cell. See also Transacetylase References External links Transferases Galactosides EC 2.3.1