Maltose transacetylase of Escherichia coli: a preliminary report.

Crude extracts of Escherichia coli K12 contain an enzyme that is able to transfer the acetyl group of acetyl-co-enzyme A to maltose (maltose transacetylase). Half maximal acetylation occurs at about 20 microM acetyl-coenzyme A. Half maximal concentration of maltose has not been determined precisely, but it is clear that it exceeds 10 mM. The appearance of maltose transacetylase is not induced by growth on maltose. Mutants carrying a defect in the malT gene, the positive regulator for the well known malA and malB regions, exhibit elevated levels of maltose transacetylase. The gene coding for the enzyme is not known that mutant analysis demonstrated that it is not part of malA, malB or malT. In addition, it is clear that the enzyme is not identical with thiogalactoside transacetylase, the gene product of the lacA gene. Besides maltose, maltodextrins and thiomaltose are substrates for maltose transacetylase.