Hormone catalysis: Role of protecting and modifying reagents of sulfhydryl groups on estrogen receptor in breast cancer

Abstract

We have studied the modulation and differential sensitivity of the estrogen receptor (ER) in breast cancer in the presence of protecting or modifying agents of disulfide bonds and sulfhydryl groups present in the ER steroid-binding domain. Protecting agents such as mercaptoethanol and dithiotreitol increased the [³H]estradiol binding to ER by 25% and 50%, respectively. Modifying agents such as p-chloromercuribenzensulfonate decreased the [³H]estradiol binding by 70% and this was nearly completely abolished by N-ethylmaleimide (94%). These data indicate that disulfide bonds and sulfhydryl groups in the steroid-binding domain are intimately involved in the maintenance of a receptor structure necessary for estradiol binding.

Keywords:

• Breast cancer
• sulfhydryl groups
• disufide bonds
• estrogen receptor