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Interaction of pirprofen enantiomers with human serum albumin
Author(s) -
Oravcová J.,
Mlynárik V.,
Bystrický S.,
Šoltés L.,
Szalay P.,
Boháčik Ľ.,
Trnovec T.
Publication year - 1991
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/chir.530030506
Subject(s) - chemistry , circular dichroism , enantiomer , human serum albumin , high performance liquid chromatography , stereochemistry , serum albumin , stereoisomerism , albumin , nuclear magnetic resonance spectroscopy , stereoselectivity , molecule , chromatography , organic chemistry , biochemistry , catalysis
The interaction of pirprofen enantiomers with human serum albumin (HSA) was investigated by means of high‐performance liquid chromatography (HPLC), circular dichroism (CD), and 1 H NMR spectroscopy. HPLC experiments indicated that both pirprofen enantiomers were bound to one class of high‐affinity binding sites (n (+) = 1.91 ± 0.13, K (+) = (4.09 ± 0.64) × 10 5 M −1 , n (‐) = 2.07 ± 0.13, K (‐) = (6.56 ± 1.35) × 10 5 M −1 ) together with nonspecific binding (n′K′ (+) = (1.51 ± 0.21) × 10 4 M −1 , n′K′ (‐) = (0.88 ± 0.13) × 10 4 M −1 ). Slight stereoselectivity in specific binding was demonstrated by the difference in product n (+) K (+) = (0.77 ± 0.08) × 10 6 M −1 vs. n (‐) K (‐) = (1.30 ± 0.21) × 10 6 M −1 , i.e., the ratio n (‐) K (‐) /n (+) K (+) = 1.7. CD measurements showed changes in the binding sites located on the aromatic amino acid side chains (a small positive band at 315 nm and a pronounced negative extrinsic Cotton effect in the region 250–280 nm). The protein remains, however, in its predominantly alpha‐helical conformation. The 1 H NMR difference spectra confirmed that both pirprofen enantiomers interacted with HSA specifically, most probably with site II on the albumin molecule.