Phosphomannosyl receptor in bovine and human tissues determined by a sensitive radioimmunoassay method

A highly sensitive radioimmunoassay method has been established for the phosphomannosyl receptor using an antibody to the bovine receptor. The amount of the receptor in extracts from total membrane fractions varied remarkably in different tissues and species. The amount in liver was the highest and that in brain was the lowest among bovine tissues. Human tissues contained significant amounts of material cross-reacting to the antibody, the highest in spleen and the lowest in kidney. The physiological significance of the receptor is discussed in terms of the intracellular transport of lysosomal enzymes in human tissues.