title: Binding study of semotiadil and levosemotiadil with alpha(1)-acid glycoprotein using high-performance frontal analysis.
abstract: High-performance frontal analysis (HPFA) was used to investigate the binding properties of human alpha(1)-acid glycoprotein (AGP) with semotiadil ((R)-isomer, Ca-channel blocker) and its antipode levosemotiadil ((S)-isomer, Ca- and Na-channel blockers). An on-line HPLC system consisting of a HPFA column, an extraction column, and an analytical HPLC column was used to determine the unbound concentrations of these enantiomers, and the experimental data were subsequently subjected to the Scatchard analyses to estimate their binding parameters. The binding affinity of the (R)-isomer (K = 3.17 x 10(7) M, n = 0.74) is approximately 1.2 times stronger than that of (S)-isomer (K = 2.59 x 10(7) M, n = 0.74). An enantioselective competitive binding study indicated that both enantiomers are bound at the same site on AGP molecules.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
authors.forename: M E
authors.initials: ME
authors.lastname: Rodriguez Rosas
authors.forename: A
authors.initials: A
authors.lastname: Shibukawa
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Kuroda
authors.forename: T
authors.initials: T
authors.lastname: Nakagawa
mesh_terms: D002121:Calcium Channel Blockers / Q000097:blood*; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007700:Kinetics; D009862:Online Systems; D009961:Orosomucoid / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D012044:Regression Analysis; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D013844:Thiazoles / Q000097:blood*
chemical_list: D002121:Calcium Channel Blockers; D009961:Orosomucoid; D013844:Thiazoles; C064356:sesamodil