Non enzymatic glycation of apolipoprotein A-I. Effects on its self-association and lipid binding properties》.pdfVIP

Vo1.153, No. 3,1988 BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS June 30,1988 Pages ] 060-1067 NON ENZYMATIC GLYCATION OF APOLIPOPROTEIN A-I. EFFECTS ON ITS SELF-ASSOCIATION AND LIPID BINDING PROPERTIES Carlos Calvo, Corinne Talussot, Gabriel Ponsin and Francois Berth~z~ne INSERM U 197, Laboratoire de Metabolisme des Lipides Hopital de lAntiquaille 69321 Lyon Cdex 05, Francs Received May 5, 1988 In diabetic patients, hyperglycaemia results in the non enzymatic glycation of many proteins including apolipoprotein A-I. We purified glycated apo A-I and compared its lipid binding properties to those of normal apo A-I. Analysis of tryptophan fluorescence spectra and of fluorescence quenching in the presence of iodine showed that glycation of apo A-I induces a decrease in the stability of the lipid-apoprotein interaction% and in that of the apoprotein self-association. Repetitive ultracentrifugations of High Density Lipoprotein (HDL) samples containing radioiodinated apo A-I or glycated apo A-I revealed that glycation of the apoprotein facilitates its dissociation from HDL. These results suggest that the non enzymatic glycation of apo A-I may affect the structural cohesion of HDL particles. © 1988AcademicPress,Inc. The plasma lipopr~teins are water-soluble complexes that transport lipids in blood (i). A large body of evidences has shown that apollpoproteins interact with lipoprotein surface through amphiphilic helical segments containing opposite polar and non-polar faces (2-6). Therefore, an alteration of these structural domains might induce changes in the lipid-pr