It has been proposed by various investigators that UV radiation may be a causative factor in the formation of cataracts. Experimental models involving the structural proteins (crystallins) and enzymes of the ocular lens of various animal species have been used successfully to study the effects of near UV-A radiation both in vivo and in vitro. However, only recently has attention been given to UV-B radiation in the range of 300-33- nm. Little work has been performed to correlate UV-induced alterations in lens proteins and enzymes with changes such as increased Na+ and Ca2+ lens concentrations which are found in certain types of cataracts. The main objective of this research, thus, is to observe alterations in the structure of various ocular lens proteins and enzymes caused by near UN-B radiation plus UV-A radiation, and variaitons in ionic strength. These effects will be correlated with changes found in the structural proteins and enzymes of the ocular lens during cataract formation. To accomplish these investigations, solutions of lens crystallins or enzymes containing various electrolytes (NaCl, KCI, CaCI2, MgSO4) will be exposed to either 295 nm, 310 nm, or a combination of the two wavelengths from a 450 watt xenon lamp or 337.1 nm from a pulsed nitrogen laser and compared to non-irradiated control samples. Whole rat or bovine lenses will also be exposed to UV radiation after which the component enzymes will be isolated and analyzed. Photolysis of tryptophan residues, photoproduct formation, and alterations in configuration will be monitored using the spectroscopic techniques of fluorescence, absorbance, and Fourier transform infrared spectroscopy. Information obtained from previous steady-state fluorescence studies will be expanded to include lifetime and anisotropy data. The technique of SDS-polyacrylamide gel electrophoresis will be used to determine the extent of lysis or aggregation of protein samples and HPLC will be used to determine the effects of photooxidation by monitoring change in peptide maps of proteins digested with trypsin. Enzymes will also be monitored for changes in activity using assays from the literature.