title: Binding of urapidil to human serum albumin: dependency on free fatty acid concentration.
abstract: The interaction between free fatty acids and urapidil binding to human serum albumin (HSA) was investigated, whereby the binding properties at the coumarine binding site were influenced by the HSA fatty acid content. As has been reported for the coumarine derivative warfarin, the highest affinity of urapidil to HSA was found at the albumin fatty acid molar ratio of 1:3. Increasing the fatty acid concentration from 0 to 3 moles per mol human serum albumin caused an increase from 50% to 95% of bound urapidil. The affinity constant increased from 2.2 x 10(3) M-1 to 2.0 x 10(4) M-1 but the number of binding sites remained constant (n = 1.2). Therefore, one urapidil binding site per HSA molecule may be assumed.
authors.affiliation: Institute of Physiology, Westfälische Wilhelms-University, Münster, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Storck
authors.forename: R
authors.initials: R
authors.lastname: Kirsten
mesh_terms: D000959:Antihypertensive Agents / Q000378:metabolism*; D001667:Binding, Competitive; D002851:Chromatography, High Pressure Liquid; D004347:Drug Interactions; D006801:Humans; D019301:Oleic Acid; D009829:Oleic Acids / Q000097:blood*; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000097:blood*; D010879:Piperazines / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D012709:Serum Albumin / Q000378:metabolism*; D014859:Warfarin / Q000378:metabolism
chemical_list: D000959:Antihypertensive Agents; D009829:Oleic Acids; D010169:Palmitic Acids; D010879:Piperazines; D012709:Serum Albumin; D019301:Oleic Acid; D019308:Palmitic Acid; D014859:Warfarin; C015568:urapidil