Asymmetric and globular forms of acetylcholinesterase in mammals and birds.

Abstract

We have identified six molecular forms of acetylcholinesterase (AcChoE; acetylcholine hydrolase, EC 3.1.1.7) in extracts from bovine superior cervical ganglia. We show that three of them resemble the collagen-tailed forms of Electrophorus AcChoE in their hydrodynamic parameters, low-salt aggregation properties, and collagenase sensitivity. The six molecular forms of bovine AcChoE appear structurally homologous to the six forms of electric fish AcChoE that have previously been characterized. They include globular molecules (monomers, dimers, and tetramers) and asymmetric aggregating molecules that possess a collagen-like tail associated with one, two, and three tetramers. We propose to call the globular forms GI, G2, and G4 and the asymmetric forms A4, A8, and A12, the subscripts indicating the number of catalytic subunits. In spite of quantitative differences in their molecular parameters, the AcChoE forms from rat and chicken are clearly homologous to those of bovine AcChoE. Thus the nomenclature we introduce is very probably valid for the main AcChoE molecular forms, at least in vertebrates, and should help to clarify structural relationships and homologies among them. This model, however, does not claim to represent entirely the complex polymorphism of AcChoE, because more or less hydrophobic variants of the G forms have been observed, and because other molecular associations cannot be excluded. We discuss the significance of the globular and collagen-tailed structure for the molecular localization of AcChoE.

Regulation by exercise of the pool of G4 acetylcholinesterase characterizing fast muscles: opposite effect of running training in antagonist muscles

“…Extractions, sedimentation analyses, and measurements of AChE activity were performed as indicated in Materials and Methods. The AChE molecular forms were identified according to Bon et al (1979) on the basis of their apparent sedimentation coefficients. CAST, Gastrocnemius; PL.…”

“…Approximately 45 fractions were collected from the gradients and assayed for AChE activity as described above. The molecular forms of AChE were identified according to the nomenclature of Bon et al (1979) on the basis of their apparent sedimentation coefficients, as determined by comparison with 3 standards (Gisiger and Stephens, 1983).…”

“…and A,,). which consist of I, 2, or 3 tetramers attached to a collagen-like tail (Bon et al, 1979;Massoulie and Bon, 1982).…”

Recovery of Acetylcholinesterase Activity in the Common Carp ( Cyprinus carpio L.) After Inhibition by Organophosphate and Carbamate Compounds

“…Both AChE and ChE are inhibited by eserine but only AChE is inhibited by 1.5-bis(4-allyl dimethyl amino phenyl)pentan-3-one dibromide (BW284C51) and by an excess of substrate, for example acetylthiocholine chloride (ACh) (Augustisson and Nachmanshon 1949;Vigny et al 1978). These enzymes may be soluble, linked to the basal lamina via a collagen tail or to membrane via a glycolipid or via a hydrophobic peptide (Bon et al 1979;Massoulie and Bon 1982). The toxicity of OP and C insecticides toward AChE has been extensively studied both in insects and vertebrates (Bocquene et al 1995;Coppage and Mathews 1974;Haubruge and Toutant 1997;Sharma et al 1993).…”

Inhibition, ADME and structure based modification of IAA and IBA against acetylcholinesterase: an attempt towards new drug development for Alzheimer's disease

“…The assay protocol was based on Ellman's method (Ellman et al 1961) and AChE (EC 3.1.1.7) from the electric eel was used for the study, since both AChE from human and electrical eel shares high structural similarities (Bon et al 1979;Sussman et al 1991). An AChE solution of about 1.37 μM concentration was prepared in double distilled water containing 0.1% of BSA.…”