Serum thiols as a surrogate estimate of DNA repair correlates to mammalianlife span

Biologically occurring thiols are a sensitive estimate of the reduction/oxi dation balance of cells, being easily and reversibly converted from sulfhyd ryl to disulfide structures in proteins and amino acids. Thiols are also kn own to regulate DNA repair, especially via the influence on poly (adenosine diphosphate-ribose) polymerase activity. Here the thiol content of saturat ed ammonium sulphate-precipitated proteins from sera was correlated to a ma mmalian life span of 17 species. A dose correlation was established between the thiol-rich proteins and the life span of the mammals (r = 0.841, p < 0 .001). These data provide a strong scientific connection between mechanisms of DNA repair and oxidative stress leading to DNA damage accumulation and mutation, which may be important to the aging process.