Metabolism of D-glucose anomers in rat lens.

In lens homogenates, hexokinase displayed a greater affinity for alpha-D-glucose but a higher maximal velocity with beta-D-glucose. However, in intact lenses incubated at 10 degrees C in the presence of 4-7 mM alpha- or beta-D-glucose, no anomeric difference could be found in either the intracellular content in D-glucose and D-glucose 6-phosphate or the utilization of D-[5-3H]glucose and oxidation of D-[1-14C]glucose. Even the sorbitol content of the lens was not significantly different after 180 min perifusion at 37 degrees C in the presence of either alpha- or beta-D-glucose. It is proposed that the lack of anomeric specificity in D-glucose metabolism is attributable, at least in part, to the low turnover rate of glucose 6-phosphate in the lens, allowing for the interconversion of glucose 6-phosphate anomers.