title: Soyasaponin I, a potent and specific sialyltransferase inhibitor.
abstract: A growing number of reports demonstrate that hypersialylation, which is observed in certain pathological processes, such as oncogenic transformation, tumor metastasis, and invasion, is associated with enhanced sialyltransferase (ST) activity. There is therefore a need for the development of ST inhibitors to modulate ST activity and thus alleviate the disease processes caused by STs. In the present study, soyasaponin I had been discovered to be a potent and specific ST inhibitor by screening strategy from 7500 samples including micribial extracts and natural products. Kinetic analysis shows that it is a CMP-Neu5Ac competitive inhibitor with for ST3Gal I with an inhibition constant (K(i)) of 2.1 microM. In addition, it is only active against ST, but not against the other tested glycosyltransferases and glycosidases. Our study is the first report to discover ST inhibitor by screening method and also to provide the new chemical structure information that should be useful in the development of other novel ST inhibitors.
authors.affiliation: Institute of Biochemistry, National Yang-Ming University, Taipei, Taiwan.
authors.forename: C Y
authors.initials: CY
authors.lastname: Wu
authors.forename: C C
authors.initials: CC
authors.lastname: Hsu
authors.forename: S T
authors.initials: ST
authors.lastname: Chen
authors.forename: Y C
authors.initials: YC
authors.lastname: Tsai
mesh_terms: D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D001921:Brain / Q000201:enzymology; D019556:COS Cells; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid / Q000037:antagonists & inhibitors / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005647:Fucosyltransferases / Q000187:drug effects / Q000378:metabolism; D005700:Galactosyltransferases / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009828:Oleanolic Acid / Q000031:analogs & derivatives*; D012503:Saponins / Q000494:pharmacology*; D012799:Sialyltransferases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013379:Substrate Specificity; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase
chemical_list: D004791:Enzyme Inhibitors; D012503:Saponins; D003569:Cytidine Monophosphate N-Acetylneuraminic Acid; C056684:soyasaponin I; D009828:Oleanolic Acid; D005647:Fucosyltransferases; D005700:Galactosyltransferases; D012799:Sialyltransferases; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase