The cellular D-amino acids of Bacillus brevis.

In a previous paper (1) evidence was presented that acid hydrolysates of the cellular material of BaciZZus brevis (ATCC 10068) contained an unusually high content of amino acids of the D configuration, amounting to over 10 per cent of the total amino acids or 5 per cent of the dry weight of the cells. The n-amino acids were shown to exist in the intact cells, and not to result from racemization during acid hydrolysis, by feeding the cells to rats and measuring the n-amino acids excreted in the urine. Studies of the nature of antibiotic peptides produced by various strains of this organism (cf. (2, 3)) have demonstrated that at least two of the compounds are cyclic decapeptides containing one or more amino acid residues of the D configuration. It seemed, therefore, of interest to survey the entire amino acid composition of the cells of B. brevis to determine quantitatively the content of the various amino acids of the D configuration, and, if possible, to determine the mode of occurrence of the n-amino acids in the intact cells.