title: Electrospray ionization mass spectrometry as a tool for determination of drug binding sites to human serum albumin by noncovalent interaction.
abstract: Most proteins in blood plasma bind ligands. Human serum albumin (HSA) is the main transport protein with a very high capacity for binding of endogenous and exogenous compounds in plasma. Many pharmacokinetic properties of a drug depend on the level of binding to plasma proteins. This work reports studies of noncovalent interactions by means of nanoelectrospray ionization mass spectrometry (nanoESI-MS) for determination of the specific binding of selected drug candidates to HSA. Warfarin, iopanoic acid and digitoxin were chosen as site-specific probes that bind to the main sites of HSA. Two drug candidates and two known binders to HSA were analyzed using a competitive approach. The drugs were incubated with the target protein followed by addition of site-specific probes, one at a time. The drug candidates showed predominant affinity to site I (warfarin site). Naproxen and glyburide showed affinity to both sites I and II. The advantages of nanoESI-MS for these studies are the sensitivity, the absence of labeled molecules and the short method development time.
authors.affiliation: Biovitrum AB, Department of Structural Chemistry, SE-112 76, Stockholm, Sweden. kurt.benkestock@medivir.se
authors.forename: Kurt
authors.initials: K
authors.lastname: Benkestock
authors.forename: Per-Olof
authors.initials: PO
authors.lastname: Edlund
authors.forename: Johan
authors.initials: J
authors.lastname: Roeraade
mesh_terms: D001665:Binding Sites; D004074:Digitoxin / Q000378:metabolism; D005905:Glyburide / Q000378:metabolism; D006801:Humans; D007480:Iopanoic Acid / Q000378:metabolism; D009288:Naproxen / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D011485:Protein Binding; D012709:Serum Albumin / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014859:Warfarin / Q000378:metabolism
chemical_list: D004364:Pharmaceutical Preparations; D012709:Serum Albumin; D009288:Naproxen; D014859:Warfarin; D004074:Digitoxin; D007480:Iopanoic Acid; D005905:Glyburide