G(4) FORMS OF ACETYLCHOLINESTERASE AND BUTYRYLCHOLINESTERASE IN NORMAL AND DYSTROPHIC MOUSE MUSCLE DIFFER IN THEIR INTERACTION WITH RICINUS-COMMUNIS AGGLUTININ

Differences in glycosylation between molecular forms of acetylcholines terase (AChE) and butyrylcholinesterase (BuChE) in muscle and serum of normal and dystrophic mice have been studied by means of their adsorp tion to immobilized lectins. Application of a two-step extraction proc edure, first with saline buffer, and second with saline buffer and Tri ton X-100, brought into solution most of the muscle AChE and BuChE act ivities. The AChE activity was five times greater than that of BuChE i n normal (NM) and dystrophic muscle (DM). The AChE activity in the ser um of dystrophic mice was twice that measured in control animals, but the BuChE activity remained almost unchanged. Both AChE and BuChE in m uscle and serum bound completely to concanavalin A (Con A) and Lens cu linaris agglutinin (LCA). A(12), A(8) and G(4) AChE, but not the light G(2) and G(1) AChE forms, in NM and DM were completely adsorbed to wh eat germ agglutinin (WGA). Similarly, G, BuChE, but not the G, and G(1 ) forms, were associated to WGA. A high proportion of G(4) and G(1) AC hE and G(4) BuChE forms in mouse serum were fixed to WGA. Asymmetric A ChE in NM and DM reacted with Ricinus communis agglutinin (RCA) but th e light AChE and BuChE forms in muscle and serum did not bind to the l ectin. G(4) AChE and G(4) BuChE in NM were not recognized by RCA, but the isoforms in DM bound fully to the lectin. Serum G(4) AChE from con trol or dystrophic mice did not react with RCA, but G(4) BuChE was fix ed to the lectin. Since RCA is specific for galactose, the results sug gest that in dystrophic muscle galactose is incorporated early in G(4) AChE and this affects the level of the functional tetramers destined for insertion in the plasma membrane.