EFFECT OF VARIOUS ANALOGS OF D-GLUTAMIC ACID ON THE D-GLUTAMATE-ADDING ENZYME FROM ESCHERICHIA-COLI

Twenty-four analogues of D-glutamic acid were tested as substrates or inhibitors of the D-glutamate-adding enzyme from Escherichia coil. The best substrates were, in decreasing order of specific activity, D-ery thro-4-methylglutamic acid, D-erythro-3-methylglutamic acid, DL-homocy steic acid, /-)-trans-1-amino-3-carboxy-cyclopentanecarboxylic acid an d +/-)-trans-1-amino-3-carboxy-cyclohexanecarboxylic acid. Among the d ifferent stereoisomers, only the D-erythro isomers for methylglutamic acids, and the trans isomers for the cyclic analogs, were substrates. Apart from the D-erythro-3- and 4-methylglutamic acids and DL-homocyst eic acid, none of the examined compounds significantly inhibited the a ddition of radioactive D-glutamic acid to UDP-N-acetylmuramyl-L-alanin e.