Abstract
1. A membrane-bound peroxidase activity was isolated and purified from pooled samples of human intrauterine tissue (embryo, placenta, amnion, chorion and uterine decidua) of 4–6 weeks of gestation.
2. The H2O2-dependent guaiacol oxidation catalysed by the purified peroxidase exhibited a specific activity of 10.82 ± 1.81 μmol/min/mg protein.
3. The optimum conditions required for guaiacol oxidation catalysed by the peroxidase included 18mM guaiacol, 400μM H2O2, pH9.0, and 2μg/ml enzyme protein. The guaiacol oxidation was inhibited by KCN and NaN3 with IC50s of 17.6 and 22 μM, respectively.
4. Several other endogenous and exogenous chemicals also underwent H2O2-dependent oxidation catalysed by the purified peroxidase. These results suggest that peroxidase may be one of the major pathways of xenobiotic oxidation present in organogenesis-stage human conceptal tissues influencing the toxicity of chemicals to which the developing embryo is exposed.