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5323981 
Journal Article 
A study of caffeine binding to human serum albumin 
Krigko, A; Kveder, M; Pecar, S; Pifat, G 
2005 
Yes 
Croatica Chemica Acta
ISSN: 0011-1643
EISSN: 1334-417X 
78 
1 
71-77 
WOS:000228773500010 
Binding of caffeine to human serum albumin (HSA) was investigated with the aim of describing the binding parameters of the interaction. It was found that the results obtained by fluorescence spectroscopy are influenced by the non-negligible artifact, known as the inner filter effect due to the absorption of caffeine at the excitation wavelength (290 nm). Therefore, a suitable correction of the obtained data was performed and the binding constant for caffeine binding to HSA was estimated, revealing low affinity of caffeine for HSA K-s = (12 +/- 1) x 10(3) Mol(-1) dm(3). Further, electron paramagnetic resonance (EPR) spectroscopy, using three different positional isomers of spin labeled stearic acid, doxyl stearates, was applied to study the caffeine-HSA interaction in further detail. It was found that upon caffeine binding, the hyperfine splitting decreases for HSA labeled with 5-doxylstearate. This phenomenon may indicate either an increase in mobility or a local change in polarity sensed by reporter groups upon caffeine binding. These observations may be important for the functional characteristics of HSA. 
HSA; EPR; fluorescence spectroscopy; caffeine; binding