title: Analogs of diaminopimelic acid as inhibitors of meso-diaminopimelate decarboxylase from Bacillus sphaericus and wheat germ.
abstract: Analogs (1----6) of diaminopimelic acid have been synthesized and tested for inhibition of meso-diaminopimelate decarboxylases from Bacillus sphaericus IFO 3525 and from wheat germ (Triticum vulgaris). Difluoromethyl diaminopimelate 1 does not irreversibly inactivate or strongly competitively inhibit either enzyme. Lanthionine sulfoxides (2ab, 2c, and 2d) are good competitive inhibitors (about 50% inhibition at 1 mM) of both decarboxylases. The meso and LL-isomers of lanthionine sulfone (3ab and 3c) and lanthionine (6ab and 6c) are weaker competitive inhibitors (about 50% inhibition at 10-20 mM). The corresponding DD-isomers (3d and 6d) are less effective. The N-modified analogs are the most potent competitive inhibitors. The inhibition constant (Ki) values for B. sphaericus and wheat germ decarboxylases with N-hydroxydiaminopimelate 4 (mixture of isomers) are 0.91 and 0.71 mM, respectively; for the N-aminodiaminopimelate 5 (mixture of isomers) the Ki values are 0.10 and 0.084 mM, respectively. These N-modified analogs do not effectively inhibit L-lysine decarboxylase. None of the compounds showed any time-dependent inactivation of the decarboxylases, in contrast to behavior of other pyridoxal phosphate-dependent enzymes with analogous substrate derivatives. Possible mechanisms of inhibition are discussed. In preliminary tests for antibiotic activity 4 and 5 both gave 75% growth inhibition of Bacillus megaterium at 20 micrograms/ml in defined media. Other analogs (1----3) showed essentially no antibacterial activity.
mesh_terms: D000599:Amino Acids, Diamino / Q000494:pharmacology*; D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins; D002262:Carboxy-Lyases / Q000037:antagonists & inhibitors*; D003960:Diaminopimelic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D007700:Kinetics; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D000599:Amino Acids, Diamino; D001426:Bacterial Proteins; D003960:Diaminopimelic Acid; D002262:Carboxy-Lyases; C079912:LysA protein, Bacteria; C020031:diaminopimelic acid decarboxylase