Composition of mucopeptide from the spores of Bacillus coagulans

Spore mucopeptide was prepared by autolysis of the cortical structure of Bacillus coagulans spores. Analysis showed that it contained glucosamine, muramic acid, L-alanine, D-glutamic acid, meso-diaminopimelic acid and D-alanine in the molecular proportions 2.8:3:1.6:1.0:1.0:1.0. About 80% of the diaminopimelic acid residues had one amino group which reacted with fluorodinitrobenzene. Alanine in trace amounts was the only N-terminal amino acid detected. The presence of most of the expected free carboxyl and amino groups was confirmed by titration studies. Not all the amino sugar appeared to be N-acetylated. The results are consistent with the proposition that the spore cortical structure consists of a loosely cross-linked matrix bearing a considerable excess of carboxyl groups.