title: Multiple molecular forms of acetylcholinesterase from human erythrocyte membranes. Interconversion and subunit composition of forms separated by density gradient centrifugation in a zonal rotor.
abstract: Quantitative separation of eight multiple molecular forms of acetylcholinesterase isolated from human erythrocyte membranes was accomplished by sucrose density gradient centrifugation in a zonal rotor. Hydrodynamic properties of the four most abundant oligomers were investigated by analytical ultracentrifugation. The S20, w values obtained for these components ranged from 12.5 S to 19.0 S with corresponding molecular weights between 500 000 and 1 131 000. These oligomers are built up of 6-14 subunits. Analysis of each isolated homogenous form after storage for 6 months at 4 degrees C revealed interconversion into the original eight components. Upon addition of Triton X-100 the oligomers disaggregate to yield a single 7-S form, which reaggregates upon removal of the detergent. Such reaggregation can be prevented by chaotropic ions indicating that hydrophobic interactions are important in the formation of these oligomeric forms.
mesh_terms: D000110:Acetylcholinesterase / Q000097:blood* / Q000302:isolation & purification; D000596:Amino Acids / Q000032:analysis; D002499:Centrifugation, Density Gradient; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004910:Erythrocyte Membrane / Q000201:enzymology*; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D046911:Macromolecular Substances; D011487:Protein Conformation
chemical_list: D000596:Amino Acids; D046911:Macromolecular Substances; D000110:Acetylcholinesterase