Studies on receptor interaction of ceruloplasmin with human red blood cells.

The interaction of CP with the red blood cell (RBC) receptor was shown to be a Ca2+ dependent process and be limited by CP binding on RBC membrane which is not followed by CP transport through the membrane into RBC. The nature of receptor interaction was determined. It was shown that receptors are formed by glycoproteins of PAS1 and PAS2 (glycoforin dimer and monomer, respectively) and terminal residues of sialic acid of these glycoproteins are important for CP reception. Receptor carbohydrate specificity was determined. Biantennary structure of CP molecule carbohydrate moiety which is bound to the receptor owing to 2 structural fragments: sialic acid terminal residues and the fragment including acetylglucosamine dimer and fucose, plays the main role in CP reception.