PROPIONATE OXIDATION IN ESCHERICHIA COLI

An investigation was undertaken to determine the principal pathway of propionate oxidation in E coli E-26. Studies in a number of systems have established that propionate may be metabolized by several different pathways. Since these pathways may be differentiated by the pattern of 14CO2 evolution from specifically labelled carbon atoms of propionate, a radiorespirometric experiment was performed in which propionate-adapted E. coli E-26 was used. Under these conditions, both the rate ancffinal cumulative percentage of 14CO2 was greatest for l-14C-propionate, intermediate for 2-14C-propionate, and least for 3-14C-propionate. The observed labelling pattern is consistent with oxidation of propionate to acetate via lactate.