Effects of sialic acids and the beta-drug adrenergic blocker, propranolol, on the dynamics of human alpha 1-acid glycoprotein: a fluorescence study.
The effect of propranolol on the dynamics of human alpha 1-acid glycoprotein (orosomucoid) (sialylated and asialylated) was studied. 2-p-Toluidinylnaphthalene-6-sulfonate (TNS) bound to the protein was used as a probe. The results were identical for all samples. Excitation at the red edge of the absorption spectrum of TNS leads to an important shift (15 nm) of the fluorescence emission maximum of the probe. This reveals that emission of TNS occurs before relaxation of the amino acid dipole has time to occur. Emission from a non-relaxed state means that TNS molecules are bound tightly to the protein, a result confirmed by polarization studies. Sialic acid residues and propranolol do not affect the rigidity of the binding site of TNS.
Albani
J R
JR
Laboratoire de Biophysique Moléculaire, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
D001665:Binding Sites; D005456:Fluorescent Dyes; D006801:Humans; D009282:Naphthalenesulfonates; D009961:Orosomucoid / Q000737:chemistry*; D011433:Propranolol / Q000138:chemical synthesis / Q000494:pharmacology*; D012794:Sialic Acids / Q000494:pharmacology*; D013050:Spectrometry, Fluorescence
D005456:Fluorescent Dyes; D009282:Naphthalenesulfonates; D009961:Orosomucoid; D012794:Sialic Acids; C009497:2-(4-toluidino)-6-naphthalenesulfonic acid; D011433:Propranolol