THE CONVERSION OF 2,6-DIAMINOPIMELIC ACID-1,7-C14TO LYSINE-1-C14BY CERTAIN BACTERIA

Abstract

When 2,6-diaminopimelicacid-1,7-C14was added to growing cultures of Bacillus megaterium, Staphlococcus aureus, and Escherichia coli, 8–9% of added carbon-14 appeared in the cellular lysine. Similar experiments with Proteus vulgaris, Streptomyces griseus, Aspergillus flavus, and Lactobacillus arabinosus resulted in less than 0.3% of the added carbon-14 being incorporated into the cellular lysine. Leuconostoc mesenteroides converted 0.6% of the added DAP-1,7-C14to lysine-1-C14.Over 90% of the carbon-14 in cell lysine from B. megaterium and L. mesenteroides was found in the carboxyl carbon. This was interpreted as indicating a direct decarboxylation of DAP-1,7-C14to lysine-1-C14. About 70% of the carbon-14 in the lysine from cells of S. aureus and E. coli was found in the carboxyl carbon, thus suggesting that some lysine comes from sources other than 2,6-diaminopimelic acid.Those organisms that actively decarboxylated DAP-1,7-C14to form lysine-C14also synthesized DAP and excreted it into the culture medium during growth.