The utilization of itaconate by Pseudomonas sp

Although many micro-organisms are known to grow on itaconate [CH2:C(CO2-) CH2* CO2] as their sole source of carbon, the pathway whereby this substrate is catabolized by obligatorily aerobic bacteria, to provide both energy and the precursors of cell materials, is not established. Brightman & Martin (1961) suggested that, in P8eudomona8 sp., this branched-chain dicarboxylic acid, and its isomer mesaconate [CHR3-C(CO-):CH'CO2-], were converted into straight-chain molecules by a process of intramolecular rearrangement which was possibly akin to that involved in the formation of mesaconate from glutamate by the anaerobe Clostridium tetanomorphum (Wachsman, 1956; Barker, Wilson & Munch-Petersen, 1957; Munch- Petersen & Barker, 1958). An alternative mode of utilization of itaconate, involving its activation to itaconyl-coenzyme A followed by hydration and cleavage to acetyl-coenzyme A and pyruvate, was suggested by studies on itaconate oxidation in liver mitochondria- (Adler, Wang & Lardy, 1957; Wang, Adler & Lardy, 1961).