Biochemical Studies on McLeod Phenotype Erythrocytes

Red cells of the McLeod phenotype in the Kell blood group system have an acanthocytic morphology. The membrane protein composition analyzed on sodium dodecyl-sulfate-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 gamma AT[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.