Beta galactoside transacetylase

β-galactoside transacetylase is an enzyme that transfers an acetyl group from acetyl-CoA to galactosides, glucosides and lactosides but not to the beta-galactosidase which is coded by lacA in the lac operon of E. coli. The galactosidase acetyltransferase of the classical E.coli lac operon is an enzyme whose biological role remain unclear. Its precise function as part of the lac operon is not understood currently.

The kinetics of the enzyme were delineated in 1995.

The enzyme's cellular role may be to detoxify non-metabolizable pyranosides by acetylating them and preventing their reentry into the cell.