Regulation of protein adenosine diphosphate ribosylation in bovine lens during aging.

Adenosine diphosphate-ribosyltransferase (ADPRT) and poly-ADP-ribose glycohydrolase (poly-ADPRG) activities were investigated in the different structures of bovine lenses. These activities and protein ADP ribosylation were detected only in the lens epithelium proliferative layer. The poly-ADPR glycohydrolase activity decreased, but the poly-ADPR polymerase activity increased during aging. In lens epithelial cells of older animals, the poly-ADP-ribose level and average chain length decreased but the chain number increased. Involvement of DNA break accumulation during aging in the increase of ADPRT activity of lens epithelial cells is discussed.