Activation of d-Aspartic Acid for Incorporation into Peptidoglycan

Enzyme preparations from Streptococcus faecalis and Lactobacillus casei catalyzed the incorporation of d-aspartic acid into a peptidoglycan in the presence of uridine diphosphate acetylmuramylpentapeptide and uridine diphosphate acetylglucosamine. The reaction required ATP but was independent of either supernatant enzymes or tRNA. A d-aspartic acid-activating enzyme present in the membrane fraction has been solubilized with 2 m LiCl and purified approximately 100-fold. The preparation so obtained catalyzed the formation of equivalent amounts of β-d-aspartylhydroxamate, ADP, and inorganic phosphate in the presence of d-aspartic acid, ATP, and hydroxylamine. The intermediate formed is presumably β-d-aspartylphosphate.