The formation of D-3-phosphoglyceric acid from pentoses by Escherichia coli.

Whilst the breakdown of glucose to D-3-phospho-. glyceric acid (PGA) has been observed in a number of micro-organisms (Werkman, Zoellner, Gilman & Reynolds, 1936; Stone & Werkman, 1936a, b, 1937; Wood, Stone & Werlmaan, 1937; Still, 1940), the formation ofPGA from pentoses has so far only been observed in the case of Propionibacterium pentosaceum (Barker & Lipmann, 1949). The present investigation deals with the transformation of pentoses to PGA by Escherichia coli; it forms part of a study of the pathways of pentose fermentation. Since the fermentation of pentoses has been shown to be adaptive (Karstrom, 1938; Cohen & Scott, 1951; Cohen & Raff, 1951; Heald, 1952), the experiments were carried otut with cells which had been grown upon media containing D-xylose and L-arabinose, respectively, and, for comparison, with cells which had been grown previously in the presence of glucose.