Heparin solubilizes asymmetric acetylcholinesterase from rat neuromuscular junction

We are interested in the factors involved in the anchorage of acetylcholinesterase (AChE) to the synaptic basal lamina. Here, we report studies showing that heparin, a sulfated glycosaminoglycan, specifically solubilized AChE from endplate regions of rat diaphragm muscle. Of the several molecular forms of AChE present in that region, heparin only released the asymmetric A12 and A8 forms of the enzyme. Our results strongly support the involvement of heparin-like macromolecules in the in vivo immobilization of the collagen-tailed forms of AChE to the basal lamina of the neuromuscular junction.