Oxidation of propionic acid by Nocardia corallina.

Two pathways have been postulated for the conversion of propionic acid to pyruvic acid by liver mitochondria. Mahler and Huennekens (1953) suggested that propionic acid was oxidized to acrylic acid which was converted to pyruvic acid through Land D-lactic acids. The alternative pathway involves a direct carboxylation of propionic acid to succinic acid (Lardy and Adler, 1956; Flavin et al., 1955). An enzyme system which catalyzes the carboxylation of propionic acid has been demonstrated in Propionibacterium pentosaceum (Barban and Ajl, 1951), Chlorobium thiosulfatophilum (Larsen, 1951), Micrococcus lactilyticus (Whiteley, 1953) and Veillonella gazogenes (Delwiche et al., 1954). Cells of a thiamin deficient Nocardia corallina oxidized propionic acid to pyruvic acid which accumulated in the system. This communication includes results which suggest that two pathways operate in N. corallina for the oxidation of propionic acid.