In the last twenty years interest has grown in the role of estrone sulfatase in promoting breast tumor growth. Estrone sulfatase is an integral membrane protein that is overexpressed in breast tumor cells. A better understanding of this enzyme could lead to inhibitors that would be useful for diagnosis or treatment of breast cancer. In order to better understand this enzyme, a number of experiments were carried out to determine information about the mechanism and possible in vivo substrates for this enzyme.

Mechanistic studies included testing a group of compounds with functional groups that target an aldehyde proposed to be in the active site of estrone sulfatase. These functional groups include amines, amino ethers, hydrazides and sulfonyl hydrazides. While the inhibiton by these compounds is modest, all of the compounds are simple readily available molecules. All of these appear to covalently modify the enzyme active site. Further mechanistic studies focused on determination of kinetic isotope effects and rates of cleavage for some simple substrates of estrone sulfatase. Kinetic isotope effects as well as Kms and rates of cleavage were determined for p-acetylphenyl sulfate, p-nitrophenyl sulfate, and p-acetamidophenyl sulfate.

Other studies focused on determining whether sulfated forms of bisphenol A, a commonly found plasticizer that has been shown to have estrogenic activity, were substrates for estrone sulfatase. Both the mono and the disulfate of bisphenol A are substrates for estrone sulfatase. These studies were carried out in collaboration with two other groups in an attempt to show that naturally occurring and synthetic phytoestrogens may utilize the same pathways as estrogens in vivo.