Interaction of urea with fluorophores bound to protein surfaces

摘要: The effect of urea on the fluorescence properties 6-(p-toluidino)-2-naphthalenesulfonate (TNS) and 8-anilino-1-naphthalenesulfonate (ANS) bound to bovine serum albumin (BSA) has been studied by steady-state time-resolved emission spectroscopy. urea-induced structural changes protein are accompanied an at least three-fold decrease yield (ϕf) both TNS ANS. lifetime (τf), however, does not change much (ca. 10%). In a homogeneous medium [90% alcohol in water (v/v)], addition leads ϕf τf which is shown be due polarity-dependent twisted intramolecular charge transfer (TICT) processes. It suggested that removal some fluorophores proteins. Since almost non-fluorescent aqueous media, overall still accounted for those denatured protein. Thus spectra remain more or less unchanged. number proteins during denaturation causes reduction ϕf.