Biosynthesis of trehalose by Brevibacterium flavum: use of long range 13C-13C coupling data to characterize triose phosphate isomerase activity.

The 13C isotopic labeling pattern in the disaccharide trehalose (1,1'-alpha-alpha-D-glucose) produced by the microorganism Brevibacterium flavum when grown on a medium containing [1-13C]glucose has been determined. Long range coupling between C-1 and C-6 carbons of the glucose units can be observed in the excreted material. It is proposed that some of the 13C isotopomers in the excreted trehalose reflect the labeling pattern in (unobserved) fructose 1,6-diphosphate. Analysis of the label distribution within the framework of a steady state kinetic model allows an analysis of the contributions of the hexose monophosphate shunt and the degree of equilibration of triose phosphate isomerase. Analogous measurements on excreted glucose could be carried out in other organisms.