Different binding of propranolol enantiomers to human alpha 1-acid glycoprotein.
The binding of propranolol enantiomers to human alpha 1-acid glycoprotein was studied using high performance liquid chromatography in order to provide insight into binding models and to describe individual binding parameters of both enantiomers. The binding of (-)-propranolol was shown to be saturable with one major binding site (n = 0.81, k = 2.73 x 10(5)/M). The saturation process achieved its upper asymptotic value at drug/protein molar ratio of approximately 1. In the case of the opposite (+)-enantiomer the binding isotherm did not show evidence of saturation even at higher drug/protein molar ratios (up to 50). The individual binding parameters for (+)-enantiomer were n = 0.38, k = 3.4 x 10(6)/M and n'k' = 1.39 x 10(4)/M for the saturable and nonsaturable binding component, respectively. At drug/protein molar ratio 2 the circular dichroism measurements confirmed the existence of different binding models for individual propranolol enantiomers.
Institute of Experimental Pharmacology, Slovak Academy of Sciences, Bratislava, Czechoslovakia.
J
J
Oravcová
S
S
Bystricky
T
T
Trnovec
D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D006801:Humans; D009961:Orosomucoid / Q000378:metabolism*; D011433:Propranolol / Q000097:blood*; D011485:Protein Binding; D011487:Protein Conformation; D013237:Stereoisomerism
D009961:Orosomucoid; D011433:Propranolol