Changes in the C-terminal region of alpha-A crystallin during human cataractogenesis

Reverse phase chromatography was used to purify alpha-A crystallin from total protein of human cataractous and normal lenses, followed by tryptic digestion and quantitation of the peptides corresponding to the intact C-terminal region of the protein. Relative to alpha-A crystallin from normal lenses, alpha-A crystallin from cataractous lenses contained decreased amounts of the expected C-terminal tryptic peptides. In an alternative approach, antiserum specific for the C-terminal region of the protein was used to quantitatively probe Western blots of total proteins from cataractous and normal lenses. The results demonstrated a decrease in the amount of this antiserum binding to the C-terminal region of alpha-A crystallin from human cataracts. Together, these studies show that relative to alpha-A crystallin from normal lenses, there is a decrease in the amount of the intact C-terminal region during the process of human cataractogenesis.