Biochemical Studies on McLeod Phenotype Erythrocytes

Abstract. Red cells of the McLeod phenotype in the Kell blood group system have an acanthocytic morphology. The membrane protein composition analyzed on sodium dodecylwlfate-polyacrylamide gel electrophoresis, the ATP level and the activities of a large number of intracellular enzymes appear to be normal. Membranes prepared from McLeod red cells incubated with γAT[³²P] and MgCl₂ incorporated twice as much radioactivity into spectrin and also showed a slight elevation of phosphorylation in band 3 protein when compared to membranes from normal cells. Intact normal red cells incubated with carrier-free [³²P] incorporated radioactivity into several proteins. with most incorporation in spectrin and band 3 protein. In comparison, McLeod cells incorporated three times more radioactivity into spectrin and band 3 protein but increased phosphorylation also occurred in other, but not all, membrane proteins. Intact McLeod red cells also showed increased phosphorylation of membrane phospholipids, but they incorporated [³²P] into intracellular nucleotide phosphates in a normal manner.