Estrone sulfatase: probing structural requirements for substrate and inhibitor recognition.
The enzyme-catalyzed desulfation of steroids is a transformation that plays an important role in steroid biosynthesis. Conversion of steroid sulfates to unconjugated steroids may provide a source of steroids for processes such as steroid transport and the growth and proliferation of breast cancer. Steroid sulfatase catalyzes the hydrolysis of 3beta-hydroxysteroid sulfates. To identify structural features important in enzyme-inhibitor interaction, a variety of steroidal and non-steroidal phosphate esters were synthesized and tested as inhibitors of steroid sulfatase activity. We report that the basic structure for enzyme-inhibitor binding does not include the steroid nucleus. Furthermore, the hydrophobicity of the non-steroidal phosphates was determined to be an important factor for optimal inhibition. The monoanionic form of the phosphorylated compounds was found to be the inhibitory species. The best non-steroidal inhibitor of steroid sulfatase activity was n-lauroyl tryamine phosphate with a Ki of 3.6 microM and 520 nM at pH 7.5 and 7.0. The poorest non-steroidal based inhibitor of sulfatase activity was tetrahydronaphthyl phosphate with a Ki of 870 and 360 microM at pH 7.5 and 7.0.
Anderson
C
C
Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.
Freeman
J
J
Lucas
L H
LH
Farley
M
M
Dalhoumi
H
H
Widlanski
T S
TS
D002863:Chromogenic Compounds; D003687:Dehydroepiandrosterone / Q000031:analogs & derivatives / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D004970:Estrone / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D010755:Organophosphates / Q000378:metabolism; D010920:Placenta; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D013429:Sulfatases / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism; D014439:Tyramine / Q000031:analogs & derivatives / Q000378:metabolism; D014867:Water
D002863:Chromogenic Compounds; D004791:Enzyme Inhibitors; D010755:Organophosphates; D013431:Sulfates; D014867:Water; D004970:Estrone; D003687:Dehydroepiandrosterone; D013429:Sulfatases; C020121:estrone sulfatase; D014439:Tyramine