D-erythrose metabolism in a strain of Alcaligenes faecalis.

Except for the oxidation of erythritol to L-erythrulose by Acetobacter (Bertrand, 1900) little is known of the metabolism of tetroses in microorganisms. Barker and Lipmann (1949) found erythritol to be esterified and oxidized by Propionibacterium pentosaceum, although a tetrose intermediate was not identified. The utilization of D-erythrose by mammalian liver slices has been reported by Abraham and Chaikoff (1955). Accumulating evidence for the biological significance of this sugar includes the recent demonstration of D erythrose -4 phosphate (E-4-P) as an intermediate in the pentose phosphate pathway (for a review see Horecker and Mehler, 1955) and in the biosynthesis of shikimic acid (P. R. Srinivasan and D. B. SprinsOn, personal communication). Chemical synthesis of E4-P has been achieved by Ballou et al. (1955). The synthetic compound has been reported by Kornberg and Racker (1955) to be identical with the enzymatically formed product. To explore further the pathways by which erythrose may be metabolized, bacteria which were able to utilize this compound as their sole carbon source were isolated by enrichment culture. From one of these organisms a cell-free preparation capable of metabolizing erythrose was prepared. Preliminary studies suggest that E4-P is produced in this cell-free system.