STUDIES ON L-THREOSE AS SUBSTRATE FOR ALDOSE REDUCTASE - A POSSIBLE ROLE IN PREVENTING PROTEIN GLYCATION

L-threose is a product of ascorbate oxidation and degradation. By virt ue of its free aldehyde group it can form Schiff-bases with tissue pro teins, altering their normal function. In this study, we have examined the possibility of its detoxification to L-threitol by aldose reducta se in the lens. The rat lens enzyme present in fresh homogenate as wel l as after 100 fold purification was found to utilize L-threose with a km of 7.1 x 10(-4) M. The specificity of the reaction was affirmed by its inhibition with sorbinil and quercetin, the well known aldose red uctase inhibitors. Further studies on the role of this enzyme in preve nting toxicity due to degradation products of ascorbate are in progres s.