Md. Gayeseye et al., FLUORESCENCE STUDIES OF THE BINDING OF 2 NATURAL ALKALOIDS (CINCHONINE AND CINCHONIDINE) WITH BETA-LACTOGLOBULIN, Journal de chimie physique et de physico-chimie biologique, 94(1), 1997, pp. 31-36
The binding to the transport protein beta-lactoglobulin (beta-LG) of t
he natural alkaloids stereoisomers, cinchonine and cinchonidine, has b
een investigated in a pH 7.5 buffer solution by fluorescence spectrosc
opy. The large decrease of beta-LG fluorescence brought about by addit
ion of cinchonine and cinchonidine has been correlated to an increase
of the complex emission, indicating an efficient energy transfer. The
complex affinity constants have been evaluated. The results clearly sh
ow that only one binding site is affected in the dimeric protein, and
that the affinity of cinchonine for beta-LG is much more important tha
n that of cinchonidine.