Finally, as mammalian peroxidases are key regulators of redox balance and free radical activity, our lab has also conducted detailed investigations into their properties and interactions with the female productive system. For instance, we have characterized many possible pathways of inhibition for MPO, a peroxidase we have also linked to deterioration of oocyte quality. In particular, the interaction of HOCl and peroxidases such as MPO and lactoperoxidase (LPO) we have found to be a possible major source of free iron release through heme destruction. This process is inhibited by substances such as melatonin, and it is also regulated by the crosstalk between catalase and MPO as per our recent studies. LPO activity, i.e. synthesis of hypothiocyanous acid, is also important to redox balance in biological systems, and LPO’s interaction with substrates such as mesna and other thiol compounds are currently under investigation in our lab. The elucidation of the biochemistry of peroxidases in our lab promises to explain important factors in the maintenance of redox balance in the female reproductive system and beyond, providing discrete pharmaceutical targets for treatment of disorders such as infertility due to degraded oocyte quality.