RESUMO
The interaction of alizarin yellow R(AYR) and bovine serum albumin (BSA) was investigated by fluorescence method in alkali buffer solution. It was shown that AYR had a powerful ability to quench the BSA fluorescence at excitation and emission wavelengths of lambda(ex) = 393 nm and lambda(em) = 641 nm in the medium solution of pH 11.00, and there were five binding sites of AYR to BSA; The combination reaction of AYR with BSA was a static quenching process, and from the effects of temperature on the fluorescence quenching rate of AYR-BSA and the Stern-Volmer quenching constant (K(SV)) and the Lineweaver-Burk quenching constant (K(LB)), the binding constant was calculated to be K = 1.6 x 10(4) L x mol(-1); as the enthalpy change deltaH(theta) < 0 and entropy change deltaS(theta) < 0, and AYR has an ability to quench the BSA-CBBG fluorescence, it can be deduced that the Van der Walls force and hydrogen bond are the main binding forces between AYR and BSA.
