Utilization of D-glucose-1-C14 by Torula utilis yeast. II.

In a previous publication (l), data were reported concerning n-mannose and n-ribose isolated from Torula utilis yeast which had been grown on n-glucose-l-C’4 as the sole source of carbon. It was found that water extraction of the lyophilized yeast yielded a mannan that was completely devoid of radioactivity. Further, the D-ribose obtained from the purine ribosides of the nucleic acid fraction showed a low specific radioactivity, suggesting that the major pathway for its production was via the oxidative decarboxylation and isomerization of n-gluconic acid 6-phosphate. The present report is concerned with the separation from the same yeast sample, by extraction with 6 per cent sodium hydroxide solution, of a second, radioactive mannan composed of polymerized n-mannose-1-C14. Further alkaline extraction, with 30 per cent potassium hydroxide solution, yielded a polysaccharide fraction containing both radioactive n-glucose and n-mannose.