| Abstract: | The utilization of ribose by Veillonella alcalescens has been further investigated. Nonfermentation of ribose is not a result of a phosphorylation lesion since ribose-phosphorylating activity was measured in cell extracts. Resting cells accumulated ribose-5-phosphate and nucleotides when 14C-ribose was provided; no other sugar phosphates were detectable. Resting cells that were shifted to growth conditions polymerized rather than degraded the accumulated ribose compounds. Cell extracts contained a fructose diphosphate phosphatase. Ribose-5-phosphate, glucose-6-phosphate, and fructose-6-phosphate were not hydrolyzed. It is postulated that the nonfermentation of ribose is not due to any metabolic lesions, but is a consequence of metabolic control at the fructose diphosphate level of glycolysis. |
