The formation of glyoxylate and succinate from tricarboxylic acids by Pseudomonas aeruginosa

Abstract

Whole dried cells and cell-free extracts of P. aeruginosa and P. fluorescens are capable of forming glyoxylate and succinate from citrate, cis-aconitate or isocitrate. Glyxylate was identified chromatographically as well as by isolation and melting-point determination of the 2:4-dinitrophenyl-hydrazone. The reaction is reversible. Crude extracts synthesize citrate from glyoxylate plus succinate. Ethylene-diaminetetraacetic acid and pyrophosphate strongly inhibit glyoxylate formation. Partially purified enzyme preparations require both an inorganic and an organic cofactor. Citrate is ruled out as a true substrate for the enzyme. Either cis-aconitate or natural (+)- isocitrate appears to be the substrate. Synthetic (+)-isocitrate may inhibit glyoxylate formation. All results are consistent with the postulation that the Cg substrate is cleaved directly to a C2 and a C4 acid.