Km. Hirshfield et al., STEADY-STATE AND TIME-RESOLVED FLUORESCENCE MEASUREMENTS FOR STUDYINGMOLECULAR-INTERACTIONS - INTERACTION OF A CALCIUM-BINDING PROBE WITH PROTEINS, Biophysical chemistry, 62(1-3), 1996, pp. 25-38
The binding of 2-[(2-bis-[carboxymethyl] hylphenoxy)-methyl]-6-methoxy
-8-bis[carboxymethyl] aminoquinoline, the fluorescent calcium probe Qu
in2, to serum albumin and several other proteins has been investigated
. Changes in fluorescence emission spectra and fluorescence anisotropy
revealed interactions between Quin2 and several proteins including hu
man serum albumin, bovine serum albumin, aldolase, phosphoglucose isom
erase, glyceraldehyde-3-phosphate dehydrogenase, and alkaline phosphat
ase. Protein-probe interactions were inhibited by the presence of calc
ium. Binding was also measured by resonance energy transfer and gel pe
rmeation chromatography. Equilibrium binding constants for Quin2 were
quantitated by the application of the recently-developed 'SPECTRABIND'
program to spectroscopic data (D. Toptygin and L. Brand, Anal. Bioche
m., 224 (1995) 330-338). Binding of Quin2 to human serum albumin is di
scussed in terms of the published X-ray crystal structure of human ser
um albumin (X.M. He and D.C. Carter, Nature, 358 (1992) 209-215).