Enantioselective binding interaction of the metolachlor pesticide enatiomers with bovine serum albumin--a spectroscopic analysis study.
Enantioselective binding interaction of the pesticides, metolachlor (RAC-metolachlor) and its S-enantiomer (S-metolachlor), with bovine serum albumin (BSA) was investigated by fluorescence and UV-vis absorption spectroscopy. Both RAC- and S-metolachlors quenched the intrinsic fluorescence of BSA via a static mechanism, and various binding parameters indicated that electrostatic forces were involved in the binding of both of these compounds. Site marker competitive experiments demonstrated that S-metolachlor bound to site I of BSA, while R-metolachlor bound to site II, indicating the importance of enantiomeric factors for binding site selection. Further experiments showed that S-metolachlor had a higher binding affinity to BSA than R-metolachlor. The obtained spectral data were resolved with use of the multivariate curve resolution-alternating least squares method (MCR-ALS), and the extracted concentration profiles of the reacting species in the interaction were obtained. These profiles indicated that S-metolachlor was the main active constituent of RAC-metolachlor for binding with BSA, and these findings have significant implications in providing an explanation why S-metolachlor is the preferred herbicide in practice than RAC-metolachlor.
State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China. ynni@ncu.edu.cn
Yongnian
Y
Ni
Fangyuan
F
Zhang
Serge
S
Kokot
D000042:Absorption; D000081:Acetamides / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002417:Cattle; D007052:Ibuprofen / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D010575:Pesticides / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D013816:Thermodynamics; D014859:Warfarin / Q000737:chemistry / Q000378:metabolism
D000081:Acetamides; D010575:Pesticides; D012710:Serum Albumin, Bovine; D014859:Warfarin; D007052:Ibuprofen; C051786:metolachlor