THE INCORPORATION OF LABELLED AMINO SUGARS BY BACILLUS SUBTILIS

1. N-Acetyl[1-(14)C]glucosamine (10mum-5mm) is incorporated by cells of Bacillus subtilis at a constant rate (0.2-2mmumoles/mg. dry wt./hr.). The rate of [1-(14)C]glucosamine (2.5mum-5mm) incorporation is proportional to the concentration; it approaches that of N-acetyl[1-(14)C]glucosamine at 5mm. 2. Label from N-acetyl-[1-(14)C]glucosamine and [1-(14)C]glucosamine is incorporated predominantly into the ;hot-trichloroacetic acid-soluble' and ;residue' fractions of cells. Acid hydrolysis of the hot-trichloroacetic acid-soluble fraction yields mainly [(14)C]glucosamine; hydrolysis of the residue fraction yields [(14)C]glucosamine and [(14)C]muramic acid. The label from N-[1-(14)C]acetylglucosamine and sodium [1-(14)C]acetate enters most cell fractions. Incorporation of N-[1-(14)C]acetylglucosamine is inhibited by the addition of unlabelled acetate. 3. Glucose competes with [1-(14)C]glucosamine for incorporation. N-Propionylglucosamine and N-formylglucosamine compete with N-acetyl[1-(14)C]glucosamine. 4. Cells pregrown on N-acetylglucosamine or glucosamine incorporate up to ten times as much N-acetyl[1-(14)C]glucosamine or [1-(14)C]glucosamine in a given time as cells pregrown on glucose.