Characterization of water-insoluble proteins in human lens nuclei

Water-insoluble proteins from the nuclei of human normal and cataractous lenses were analyzed by solubilizing the lens material in various organic solvent/water mixtures. Gel permeation chromatography with TSK-3000 and TSK-4000 columns and a high performance liquid chromatography system were utilized to fractionate the water-insoluble proteins. The effective solvent systems were a) acetonitrile:tetrahydrofuran: water = 20:60:20, v/v%; b) tetrahydrofuran:water = 50:50, v/v%; and c) methanol:water = 25:75, v/v%. Different protein fractions could be selectively extracted with different solvent mixtures. The fractions obtained were partially identified using antibodies made against the soluble alpha-, beta-, and gamma-crystallins. Protein profiles obtained from cataractous nuclei differed markedly from those obtained from normal nuclei of the same age. In particular, an approximately 350K protein aggregate was found to increase with age in cataractous nuclei. This 350K aggregate is only a minor component in the nuclei of normal lenses.