| The binding reactions between antimalarial agent,e.g.artemisinin（ART）or dihydroartemisinin（DHA）,and drug-metabolizing enzyme CYP2B6 were studied by fluorescence quenching spectroscopy at simulated physiological conditions. The structural information of CYP2B6 during their interactions was investigated by synchronous fluorometric method.The results showed that,for both reactions of ART with CYP2B6 and DHA with CYP2B6,the main quenching mechanism was static quenching at temperature range of 296-303 K,and turned to static quenching mixed with dynamic quenching while the temperature increased to 303-310 K.At a physiological temperature of 310 K,the bonding capability of DHA and CYP2B6 was stronger than that of ART and CYP2B6.The main bonding formation of ART to CYP2B6 system was hydrogen bond by Van Der Waals force at the temperature range of 296-303 K,and then changed to hydrophobic force when the temperature stepped up to 303-310 K.However,the main bonding force between DHA and CYP2B6 was electrostatic force at 296-303 K and changed to hydrogen bond by Van Der Waals force when the temperature grew to 303-310 K.All of the reactions were spontaneous thermodynamics reactions.And the synchronous spectra showed that both the bonding sites of ART to CYP2B6 and DHA to CYP2B6 were near to the tryptophane residue of CYP2B6,and the bonding site of DHA was closer than that of ART to the tryptophane residue.Meanwhile,both ART and DHA had little influence on the conformation of CYP2B6 at room temperature（298 K）. |