SOME INTERRELATIONSHIPS OF AMINO ACIDS IN THE NUTRITION OF LEUCONOSTOC MESENTEROIDES

Abstract

Through the use of statistically designed experi-ments, 5 separate antagonistic relationships involving glycine, L-alanine, L-serine, and L-threonine in the nutrition of L.mesenteroides P-60 were demonstrated. Glycine, L-serine, and L-threonine were mutually antagonistic, while L-alanine inhibited utilization of both glycine and L-serine. The dipeptides, glycyl-DL-serine, glycyl-DL-threonine, and glycylglycine are more efficient in relieving the particular inhibition than their component amino acids. In addition, glycylglycine is non-inhibitory under conditions where glycine markedly inhibits growth of L. mesenteroides P-60. Since resting cells of L. mesenteroides P-60 readily hydrolyze the above dipeptides, it is believed that in these anta-gonisms the free amino acid is antagonized during the absorption proc-ess, whereas the peptide passes uninhibited. The non-inhibitory nature of glycylglycine under conditions in which glycine is markedly inhibitory supports this idea and indicates an additional condition under which appropriate peptides may surpass their component amino acids in promoting the growth of bacteria.