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 acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in muscle and serum of normal and dystrophic mice have been studied by means of their adsorption to immobilized lectins. Application of a two-step extraction procedure, first with saline buffer, and second with saline buffer and Triton X-100, brought into solution most of the muscle AChE and BuChE activities. The AChE activity was five times greater than that of BuChE in normal (NM) and dystrophic muscle (DM). The AChE activity in the serum of dystrophic mice was twice that measured in control animals, but the BuChE activity remained almost unchanged. Both AChE and BuChE in muscle and serum bound completely to concanavalin A (Con A) and Lens culinaris 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 wheat 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) AChE and G(4) BuChE forms in mouse serum were fixed to WGA. Asymmetric AChE in NM and DM reacted with Ricinus communis agglutinin (RCA) but the light AChE and BuChE forms in muscle and serum did not bind to the lectin. 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 control or dystrophic mice did not react with RCA, but G(4) BuChE was fixed to the lectin. Since RCA is specific for galactose, the results suggest 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.