An enzymatic study of the utilization of gluconic acid by Propionibacterium pentosaceum.

Generally the so-called Meyerhof-Embden scheme is considered to be the major pathway of hexose dissimilation by members of the genus Propionibacterium. Two lines of evidence supporting this premise are the isolation, coupled with a demonstration of their utilization, of several of the intermediates of glycolysis (Wood, Stone, and Werkman, 1937; Werkman, Stone, and Wood, 1937; Barker and Lipmann, 1949) and the distribution of a major portion of the isotopic labeling of various carbohydrates in the product commensurate with such a pathway (Wood, Stjernholm, and Leaver, 1955). There is additional evidence, however, for the existence of simultaneous alternate pathways of carbohydrate dissimilation by this microbe. Indicative of such alternate pathways is the relative insensitivity of glucose dissimilation and oxidation by Propionibacterium to the inhibitors of normal glycolysis (Werkman, Stone, and Wood, 1937; Fukui, 1952) and isotopic data best explained by additional pathways (Wood, Stjernholm, and Leaver, 1955). However, studies of carbohydrate utilization on an enzyme level with this organism have been lacking. Fukui (1952) while studying the ability of various species of the genus Propionibacterium to adapt to aerobic growth, noted that various members of this group were capable of utilizing sodium gluconate as an energy source. Since the utilization of gluconate is generally considered to be indicative of a pathway or pathways alternate to conventional glycolysis (Gunsalus, Horecker, and Wood, 1955), an enzymatic study of gluconate dissimilation by Propionibacterium pentosaceum strain E214 seemed significant. Growth of this organism on sodium gluconate presumably has the advantage of inducing greater activity of the pathways alternate to conventional glycolysis and thus their enzymatic study is quantitatively facilitated.