MOLECULAR BASIS OF AGING
Harman, D. Aging- a theory based on free-radical and radiation-chemistry. J. Gerontol. 1956;11:298-300.
Abstract: This paper describes a theory about mechanisms of aging that is based on free radical chemistry: "Aging and the degenerative diseases associated with it are attributed basically to the deleterious side attacks of free radicals on cell constituents and on the connective tissues. The free radicals probably arise largely through reactions involving molecular oxygen catalyzed in the cell by oxidative enzymes and in the connective tissues by traces of metals such as iron, cobalt, and manganese."
Full text: http://sageke.sciencemag.org/cgi/reprint/2002/37/cp14.pdf
Harman, D. The biologic clock: the mitochondria? J. Am. Geriatr. Soc. 1972;4:145-147.