A chiral probe for the acute phase proteins alpha-1-acid glycoprotein and alpha-1-antitrypsin based on europium luminescence

Reversible and selective binding of a dynamically racemic europium(III) complex to alpha(1)-acid glycoprotein and alpha(1)-antitrypsin is characterised by a significant change in the europium total emission spectral fingerprint and the switching on of a large circularly polarised luminescence (CPL) signal from the metal centre. Observation of an induced CD into the ligand chromophore in the presence of alpha(1)-AGP allows a structure for the protein-bound complex to be postulated. A direct determination of elevated alpha(1)-AGP levels in human serum was achieved by monitoring changes in the intensity ratio of Eu emission bands.