Interaction of bilirubin with human erythrocyte membranes. Bilirubin binding to neuraminidase- and phospholipase-treated membranes.
Saturable bilirubin binding to human erythrocyte membranes was measured before and after digestion with neuraminidase and phospholipases. Neuraminidase-treated erythrocyte membranes did not show any change in their binding properties, indicating that gangliosides could be excluded as candidates for saturable bilirubin-binding sites on erythrocyte membranes. Although bilirubin-binding properties of the membranes did not change after phospholipase D digestion, either, phospholipase C treatment greatly enhanced bilirubin binding. Thus it is suggested that a negatively charged phosphoric acid moiety of phospholipids on the membrane surface may play a role to prevent a large amount of bilirubin from binding to the membranes. Further saturable bilirubin binding to inside-out sealed erythrocyte membrane vesicles showed values comparable with those of the right-side-out sealed membranes, suggesting that the bilirubin-binding sites may be distributed on both outer and inner surfaces of the membranes, or may exist in the membranes where bilirubin may be accessible from either side.
Sato
H
H
Department of Perinatology, Aichi Prefecture Colony, Japan.
Aono
S
S
Semba
R
R
Kashiwamata
S
S
D001663:Bilirubin / Q000097:blood*; D002794:Choline / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008055:Lipids / Q000494:pharmacology; D009439:Neuraminidase / Q000494:pharmacology; D010739:Phospholipase D / Q000494:pharmacology; D010743:Phospholipids / Q000494:pharmacology; D013053:Spectrophotometry; D010738:Type C Phospholipases / Q000494:pharmacology
D008055:Lipids; D010743:Phospholipids; D010738:Type C Phospholipases; D010739:Phospholipase D; D009439:Neuraminidase; D002794:Choline; D001663:Bilirubin