Proteolytic fragmentation of spectrin:effect of removal of terminal phosphopeptides on spectrin binding to human erythrocyte membranes.

The involvement of phosphorylated regions of spectrin, from human erythrocytes, in membrane binding has been investigated. Spectrin is phosphorylated at several sites, all near a terminal of the band 2 polypeptide. This region can be removed from the bulk of the molecule by brief trypsinization. Membrane binding of the bulk of the protein is unaffected by brief proteolysis, whereas phosphofragments generated by this treatment exhibit no membrane binding.