THE MALONIC DECARBOXYLASE OF PSEUDOMONAS AERUGINOSA

Abstract

Dried cell prepns. of malonate-adapted P. aeruginosa decarboxylate malonic acid under aerobic and anaerobic conditions with the accumulation of acetic acid. The reaction products were identified and C balances show that the reaction is malonate[long dash]> acetate + CO2. The crude enzyme responsible for this reaction has been obtained in a cell free form, and some properties of a new enzyme, malonic decarboxylase, are described. Dried and cell free prepns. decarboxylate only one other conventional substrate, oxalacetate. The oxalacetate decarboxylase is not malonate sensitive. Malonic decarboxylase and a malonate sensitive succinic dehydrogenase may coexist in the same cell. In such cells malonic decarboxylase gradually relieves malonate inhibition of succinic dehydrogenase.