Effect of metal ions on binding of bilirubin to erythrocyte membranes.

ABSTRACT

Binding of bilirubin to different erythrocyte membranes, namely, human, buffalo, sheep and goat, pre-incubated with different concentrations of metal ions was studied. The results showed that among the different metal ions used, Ca2+ had the highest potential in increasing the amount of bound bilirubin followed by Sr2+ and Mg2+, whereas Ba2+ had the lowest potential. Treatment of these membranes with Ca2+ led to an increase in the amount of bound bilirubin in all membranes. However, human erythrocyte membranes pretreated with Ca2+, bound the highest amount of bilirubin compared to other erythrocyte membranes. Increase in bilirubin binding upon Ca2+-treatment can be ascribed to shielding effect, redistribution of phospholipids as well as increase in surface hydrophobicity induced by Ca2+.