Cataract disease has been linked to the formation of toxic aldehydes following oxidative stress and to sorbitol accumulation in the diabetic condition. Alpha-Glycerol-P levels have been shown to increase in the presence of high glucose and upon glutathione depletion. The research goals of this proposal are to study enzymic pathways in the human lens that can clear aldehydes (aldehyde dehydrogenase and glyceraldehyde-3-P dehydrogenase); convert sorbitol to fructose (polyol dehydrogenase); and, direct the metabolism of G-3-P to Alpha-glycerol-P formation (triosephosphate isomerase and Alpha-glycerol-P dehydrogenase). We plan to assess the role of phosphodiesterase in c AMP regulation and point out that certain of these enzymes contribute to the heterogeneity of the polypeptide population of the Beta-crystallins of the human lens. We plan to purify the major charge forms of these enzymes; establish the kinetic requirements that lead to their optimal activity; and, establish whether or not a change in the biochemical properties and biophysical characteristics (distribution of charge forms) can be attributed to age, the type and origin of cataract disease, and to oxidative stress. Isolation techniques are to include FPLC molecular seive and anion exchange chromatography, as well as chromatofocusing. It is our working hypothesis that if we know the precise factors that effect the activity of these enzymes in vitro, we can either maintain or modify their catalytic capacity in vivo.
