ANALYSIS OF THE BINDING OF CHLORPHENIRAMINE TO HUMAN SERUM-ALBUMIN BY SPECTROSCOPIC TECHNIQUES

The binding of chlorpheniramine (CFA) to human serum albumin (HSA) has been studied by absorption and fluorescence techniques. By deconvolution of the UV-spectra into five Gaussian bands it can be observed that the band at 214 MI is the most sensitive for following the interaction CFA-HSA. Such interaction causes a redshift in the band at 227 nm to 235 nm, and an isosbestic point surges at 236 nm. Moreover, the fluorescence quenching depends on the excitation wavelength. By excitation at 278 nm, 25% of the native fluorescence is quenched, but only 6% is quenched by excitation at 290 nm. From these spectroscopic studies our results are compatible with the possibility that the interaction could take place mainly on the subdomain IIIA.