A uridine diphosphoacetylmuramyl hexapeptide from penicillin-treated Streptococcus faecalis.

Uridine diphosphoacetylmuramyl peptide compounds were first isolated from penicillin-treated Staphylococcus aureus, in which they accumulate (1). The major compound that accumulates in this circumstance contains five amino acids and is represented as UDP-Glu’.lc-lactyl-L-Ala-n-Glu-L-Lys-o-;llan-Ala1 (l-3). This compound is believed to be a precursor of the cell wall, which contains, among other constituents, acetylmuramyl peptide fragments, at least some of which are presumably identical with that in the nucleotide (4). In Escherichia coli, an organism that contains meso-oc , c-diaminopimelic acid in the basal structure of the cell wall in place of L-lysine, a uridine nucleotide was isolated containing meso-a , c-diaminopimelic acid in place of L-lysine in the peptidc sequence (5). ,4 small degree of uridine nucleotide accumulation induced by penicillin in a strain of Streptococcus faecalis will be reported in the present paper. The accumulated compounds have been isolated and include a UDP-acetylmuramyl pentapeptide and a novel UDP-acetylmuramyl hexapeptide.