The biosynthesis of guanosine diphosphate mannose and phosphomannan by Hansanula holstii

The biosynthesis of phosphomannan by cultures of Hansenula holstii NRRL Y-2448 has been demonstrated to proceed from glucose with all carbons remaining intact. Enzymes were found in cell-free extracts capable of converting glucose to guanosine diphosphate mannose via mannose 1-phosphate. The isomerization of glucose to mannose occured as hexose phosphate and not as nucleotide hexose. The isolation and identification of guanosine diphosphate mannose from perchloric acid extracts gave further evidence for the proposal that guanosine diphosphate mannose is a precursor of phosphomannan.