Carbonyl modification in rat liver histones: decrease with age and increase by dietary restriction.

We studied carbonylation, a form of oxidative modification of proteins, of histones in rat livers. Histones H1, H2B/H2A, and H3 were significantly carbonylated but the modification was almost undetectable in H4. Contrary to the generally accepted view of increased protein carbonylation with age, the modification of histones was significantly lower in old (30-month-old) than in young (5-month-old) animals. Dietary restriction of older animals for 2 months resulted in increase in carbonylation comparable to that at the young level. These findings may have physiological implications in chromatin structure/function in aging and beneficial effects of DR by influencing transcription, replication, and/or repair activities.