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Enantiospecific binding of Rotigotine and its antipode to serum albumins: Investigation of binding constants and binding sites by partial‐filling ACE
Author(s) -
Chu BaoLin,
Lin JinMing,
Wang Zhihua,
Guo Baoyuan
Publication year - 2009
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200800521
Subject(s) - enantiomer , chemistry , binding site , human serum albumin , bovine serum albumin , serum albumin , binding constant , albumin , chromatography , stereochemistry , biochemistry
Enantiospecific binding of antiparkinsonian medication Rotigotine ( S ‐enantiomer) and its antipode to HSA or BSA was demonstrated employing partial‐filling ACE (PF‐ACE) under near‐physiological conditions (50 mM phosphate, pH 7.4, 37°C). The enantioseparation of the enantiomers was achieved by PF‐ACE. Subsequently, the binding characteristics of the enantiomers to the serum albumins were investigated. Based on the PF‐ACE data, the following binding constants were obtained: K b,HSA,S =8884±255 M −1 , K b,HSA,R =17648±587 M −1 , K b,BSA,S =7348±237 M −1 , K b,BSA,R =9353±352 M −1 . It revealed that Rotigotine had weaker affinity for the two serum albumins, and both enantiomers showed stronger affinity for HSA than BSA. The presence of either site marker (warfarin or ketoprofen) had adverse effect on the enantioseparation due to the competitive binding, or even eliminated the enantioselective binding of the enantiomers to the albumin when the molar ratio of the site marker to the albumin was at certain level. Although there might be a synergistic binding between the drug and the albumin, it was suggested that site II and I were the preferential binding site of the drug on HSA and BSA, respectively.