Fibroblasts were exposed to various concentrations of hydrogen peroxide and
the removal of oxidized proteins was followed by determining protein-bound
carbonyls, Fibroblasts are able to increase the turnover of metabolically
radiolabeled proteins after treatment with hydrogen peroxide, It was demons
trated for the first time, that the increased protein turnover was accompan
ied by a removal of protein-bound carbonyl groups. The proteasome-specific
inhibitor lactacystin was able to inhibit the elimination of protein-bound
carbonyl groups. Therefore, the key role of the proteasome in the degradati
on of oxidized proteins in fibroblasts could be demonstrated, (C) 1998 Fede
ration of European Biochemical Societies.