Determination of absolute configurations of 4-hydroxyequilenin-cytosine and -adenine adducts by optical rotatory dispersion, electronic circular dichroism, density functional theory calculations, and mass spectrometry.

ABSTRACT: Estrogen components of some hormone replacement formulations have been implicated in the initiation of breast cancer. Some of these formulations contain equine estrogens such as equilin and equilenin that are metabolized to the genotoxic catechol 4-hydroxyequilenin (4-OHEN). Auto-oxidation generates the o-quinone form that reacts with dC and dA in oligodeoxynucleotides to form unusual stable cyclic bulky adducts, with four different stereoisomers identified for each base adduct. The dC and dA adducts have the same unsaturated bicyclo[3.3.1]nonane type linkage site with identical stereochemical characteristics. Stereochemical effects may play an important part in the biological consequences of the formation of 4-OHEN-DNA adducts, and the assignment of the absolute configurations of the ster

SUBMITTER: Ding S 

PROVIDER: S-EPMC2574695 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature