Glycosylation of acetylcholinesterase forms in microsomal membranes from normal and dystrophic Lama2dy mouse muscle.

The distribution and glycosylation of acetylcholinesterase (AChE) forms in vesicles derived from sarcoplasmic reticulum of normal muscle (NMV) were investigated and compared with those from dystrophic muscle vesicles (DMV). AChE activity was similar in NMV and DMV. Most of the AChE in NMV and half in DMV were released with Triton X-100. Asymmetric (A12) and globular hydrophilic and amphiphilic (G4H, G4A, G2A, and G1A) AChE species occurred in NMV and DMV, the lighter forms being predominant. The percentage of G4H and G4A decreased in DMV. A fraction of the AChE that could not be extracted with detergent was detached with collagenase. Most of the detergent-released A12 AChE from NMV and nearly half in DMV failed to bind to Ricinus communis agglutinin (RCA-I). Conversely, the collagenase-detached isoforms bound to RCA, revealing that asymmetric AChE associated with internal membranes or basal lamina differed in glycosylation. Moreover, nearly half of G4A AChE in DMV and a few in NMV bound to RCA. Most of the RCA-unreactive G4A forms in NMV come from sarcolemma. The results indicate that dystrophy induces minor changes in the distribution and glycosylation of AChE forms in internal membranes of muscle.