Abstract
Most of the methods available for general separation of proteins have been applied to the proteins of the crystalline lens. The classical work of Mörner, in 1894, suggested that there were three soluble lens proteins which he labeled α-, β- and γ-crystallin and an insoluble residue which he called albuminoid. Subsequent attempts at fractionation using differential solubility, low-voltage electrophoresis, and ultracentrifugation appeared to confirm this finding. However, utilization of high-voltage electrophoresis immunodiffusion, immunoelectrophoresis, and chromatography on modified cellulose columns showed a much larger number of fractions, i.e., ten or more. It has been recently demonstrated that separation procedures on high molecular weight proteins conducted in solutions with a high concentration of urea can cause dissociation of the proteins into smaller molecular weight components which on removal of the urea reassociate once more. It has been shown that these phenomena obtain for α- and (β-crystallins. These findings suggest that Mörner's original three soluble proteins are still the major protein components of the lens. Whether the subcomponents demonstrated by the newer separation methods have an independent biological existence is yet to be proved.