AGE-DEPENDENT LOSS OF THE C-TERMINAL AMINO-ACID FROM ALPHA-CRYSTALLIN

Antiserum made against the C-terminal region of alpha-A crystallin was used to monitor the purification of a tryptic peptide containing the C-terminus of the molecule from fetal versus adult bovine lenses. Mass spectral analysis of the peptide preparations obtained from these lenses demonstrated the presence of a peptide (T20) containing an intact C-terminus from fetal lenses and the presence of an additional peptide (T20′) from older lenses that contained a cleaved C-terminal serine. These results demonstrate an age-dependent processing of alpha-A crystallin in the bovine lens, resulting in removal of the C-terminal amino acid residue. © 1992 Academic Press Limited.