Md. Gayeseye et al., SPECTROFLUOROMETRIC STUDY OF THE PH EFFEC T ON THE COMPLEXATION OF CINCHONINE WITH BETA-LACTOGLOBULIN (BETA-LG), Journal de chimie physique et de physico-chimie biologique, 94(6), 1997, pp. 1208-1215
pH effect on complex formation between beta-LG and cinchonine is studi
ed by fluorescence spectroscopy in aqueous buffer solutions in the 5.8
5 - 8.2 pH range, where cinchonine is essentially a monocation. Specif
ic interactions were observed with very close affinity constant values
(between 17.10(3) and 23 x 10(3) M-1), throughout the investigated pH
, except pH 8.2 where no significant complexation was noted. The latte
r phenomenon may be due to a reversible structural evolution of the pr
otein occurring at pH > 7.5.