1-anilino-8-naphthalenesulphonate binding parameters in red cell membranes. Does diabetes mellitus affect cell membrane dynamics?

Abstract

In this study we report the use of 1-anilino-8-naphthalenesulphonate as a fluorescence probe to investigate the properties of plasma membranes derived from normal and diabetic red blood cells. The binding of 1-anilino-8-naphthalenesulphonate to diabetes-affected erythrocyte membranes, as compared with controls, was measured by means of fluorescence polarization and fluorescence titration techniques. These measurements demonstrated anomalous 1-anilino-8-naphthalenesulphonate binding to pathological red cell membranes. The amount of 1-anilino-8-naphthalenesulphonate bound to diabetic erythrocyte membranes was greater than that of controls. This fluorometric study indicated that the outer monolayer binding of 1-anilino-8-naphthalenesulphonate was markedly augmented in the erythrocyte membranes of diabetic patients. Significant correlations were found between 1-anilino-8-naphthalenesulphonate binding parameters and membrane lipid composition. The correlation between these binding parameters and non-enzymatic protein glycation was poor or moderate. Though the fluorescence intensity and emission maximum were quite similar in both groups investigated, binding studies revealed that there were approximately 1.2 times the number of 1-anilino-8-naphthalenesulphonate binding sites and a 33% increase in the KD value in diabetic membranes, suggesting significant differences in the environment of the 1-anilino-8-naphthalenesulphonate binding sites in these two groups of patients. The results presented in this report indicate that (a) 1-anilino-8-naphthalenesulphonate is a sensitive probe of membrane architecture alterations, and can be used to elucidate the perturbating effects of sterols in membrane systems, and (b) that significant differences in membrane dynamics exist between normal and diabetic red cell membranes.(ABSTRACT TRUNCATED AT 250 WORDS)