title: Acetylcholinesterase of Schistosoma mansoni. Molecular forms of the solubilized enzyme.
abstract: Several molecular forms of acetylcholinesterase were obtained from Schistosoma mansoni homogenates by extraction in either low-salt buffer, high-salt buffer or detergent buffer. The low-salt soluble form amounts to 25% of the total activity. By contrast, the extract obtained in the presence of Triton X-100 possessed almost almost 3-fold higher enzymatic activity, most of it (86%) being retained in the soluble extract (100 000 X g). High-salt concentration (1 M NaCl) also has a solubilizing effect, but to a lesser extent (50%). Acetylcholinesterase can also be solubilized by treatment with a solution of 1% methylmannoside (40%). In the presence of non-ionic detergents, the enzyme behaves as monodisperse 8 S form. In the absence of detergent the low-salt soluble extract is polydisperse: it contains a 10 S and a 32 S component, the latter could represent high polymers. The molecular form released from tissue homogenate by treatment with alpha-methylmannoside is polydisperse: it contains a major 10 S and a minor 32 S component. Differences in sedimentation coefficient were observed among the enzymes extracted with detergent from the various life cycle stages of the parasite. The enzyme from the cercarial stage sediments as a single 8 S peak. The adult worm exhibits an additional acetylcholinesterase peak of 18 S representing approx. 30% of the total enzymatic activity. The molecular weight of the major 8 S species, as determined by gel filtration, is 450 000.
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis*; D000818:Animals; D002499:Centrifugation, Density Gradient; D007527:Isoenzymes / Q000032:analysis*; D008766:Methylmannosides / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008970:Molecular Weight; D012550:Schistosoma mansoni / Q000201:enzymology*; D012995:Solubility
chemical_list: D007527:Isoenzymes; D008766:Methylmannosides; C008466:methylmannoside; D000110:Acetylcholinesterase