A New Type of Hexose Monophosphate Shunt in Chlorella sorokiniana: CO(2) Release from Differentially Labeled Glucose

Using differentially labeled glucose as a substrate to probe the operation of the hexose monophosphate shunt (pentose cycle) in Chlorella sorokiniana, we found that the labeling patterns for the release of ¹⁴CO₂ over the first 5 minutes are compatible with the operation of the recently described L-type pentose shunt. Experimentally, this L-type differs from the F-type or `textbook' variety in that no radioactivity is obtained from C-2 labeled glucose, and the small amount derived from C-6 labeled glucose is due to a second pass of the glucose molecule (derived from the pentose cycle) through the pentose cycle.