REACTIONS OF THE TRIFUNCTIONAL NITROGEN-MUSTARD TRIS-(2-CHLOROETHYL)-AMINE (HN3) WITH HUMAN-ERYTHROCYTE MEMBRANES INVITRO

Covalent labeling of membrane proteins and cytoplasmic components in washed human erythrocytes by the alkylating antitumor agent HN3 has been studied in vitro. Using 14C-labeled HN3 and SDS-polyacrylamide-gel-electrophoresis for separation of the reaction products the following results have been obtained: (1) The membrane protein spectrin (bands 1,2) disappeared from the SDS-polyacrylamide-gel-electrophoresis pattern. Formation of proteins with higher molecular weight suggested cross-linking of spectrin to itself and to other proteins from membrane and cytoplasm. (2) The carbohydrate containing protein glycophorin (PASI) and the protein in band 7 were labeled by the compound. Other membrane proteins reacted to a lower extent. (3) The alkylating agent penetrated the membrane and reacted with hemoglobin in the cytoplasm. The formation of globin dimers was detected. © 1979.