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Stereoselective binding of carbenicillin epimers to human serum albumin
Author(s) -
Itoh Tomoo,
Nakashima Katashi,
Tsuda Yasuyuki,
Yamada Hideo
Publication year - 1996
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/(sici)1520-636x(1996)8:2<201::aid-chir5>3.0.co;2-l
Subject(s) - stereoselectivity , chemistry , epimer , binding site , stereochemistry , human serum albumin , biochemistry , catalysis
Binding of carbenicillin (CBPC) epimers to human serum albumin (HSA) was found to be stereoselective. Epimer‐epimer interaction was also observed in the binding to HSA. There were at least three binding sites on HSA for CBPC epimers, one of which (stereoselective site) was more in favor of S‐CBPC than R‐CBPC. At the stereoselective site, the binding constant of S‐CBPC was approximately 4‐fold greater than that of R‐CBPC. The affinities to other binding sites (non‐stereoselective sites) were similar between the epimers, and the affinity of S‐CBPC of the non‐stereoselective sites was much smaller than that for the stereoselective site. R‐CBPC and S‐CBPC appeared to displace each other at all the binding sites, i.e., the binding of the epimers was competitive at the non‐stereoselective sites as well as at the stereoselective site. By using site marker ligands, it was revealed that CBPC epimers may bind to Site I (warfarin binding site), but not to Site II (diazepam binding site). A binding model with an assumption of competitive interactions at all the binding sites simulated the binding characteristics of CBPC epimers fairly well. © 1996 Wiley‐Liss, Inc.