Phosphoglucoisomerase-catalyzed interconversion of hexose-phosphates.

The rate of conversion of D-glucose 6-phosphate to D-fructose 6-phosphate as catalyzed by yeast phosphoglucoisomerase is about fourfold lower when H, rather than H, is present on the C2 of D-glucose 6-phosphate. This difference appears to be due mainly to a change in maximal velocity, rather than affinity. Phosphoglucoisomerase also distinguishes between H and H in terms of either their intramolecular transfer from C2 to C1 or their incorporation from water on the C1 of D-fructose 6-phosphate. [ABSTRACT FROM AUTHOR]