Heterogeneity of ascorbate free radical reductase in the human lens.

The soluble ascorbate free radical (AFR) reductases in the human lens were separated into many isoforms in the range of pI 5-7 by native isoelectric focusing. In the two-dimensional gel electrophoresis, however, two main proteins with molecular weights of 20-25 kD were commonly identified to each isoform. The observed heterogeneity of the human lens AFR reductase is very similar to those reported for beta- and gamma-crystallins in aged and cataractous human lenses. From these results, it is suggested that some of the isoforms of the lens AFR reductase, especially the more acidic isoforms, may be formed by posttranslational modifications.