A unique hydrophobic domain of rat brain globular acetylcholinesterase for binding to cell membranes.
Both salt-soluble and detergent-soluble rat brain globular acetylcholinesterases (SS- and DS- AChE EC 3.1.1.7) are amphiphiles, as shown by detergent dependency of enzymatic activity and binding to liposomes. Proteinase K and papain treatment transformed SS-AChE and DS-AChE into forms that, in absence of detergent, no longer aggregated nor bound to liposomes. In contrast, phosphatidylinositol-specific phospholipase C had no effect on these properties. Labeling DS-AChE with 3-(trifluoromethyl)-3-(m-(125I)-iodophenyl) diazirine ([125I]TID) revealed, by polyacrylamide gel electrophoresis under reducing conditions, one single band of 69 kD apparent molecular mass. The same pattern was previously obtained with Bolton and Hunter reagent-labeled enzyme. Proteinase K treatment transformed the 11 S [125I]TID labeled AChE into a 4 S form which no longer showed 125I-radioactivity and was unable to bind to liposomes. These results are compatible with the existence of a hydrophobic segment present both on salt-soluble and detergent-soluble 11 S AChE as well as on the minor forms 4 S and 7 S. This segment is not linked to the catalytic subunits by disulfide bounds in contrast to the 20 kD non-catalytic subunit described by Inestrosa et al.
Andres
C
C
Centre de Neurochimie du C.N.R.S., Strasbourg, France.
el Mourabit
M
M
Mark
J
J
Waksman
A
A
D000110:Acetylcholinesterase / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001389:Azirines; D001665:Binding Sites; D001921:Brain / Q000201:enzymology*; D002462:Cell Membrane / Q000201:enzymology*; D003432:Cross-Linking Reagents; D003902:Detergents; D004220:Disulfides / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D019286:Endopeptidase K; D008081:Liposomes / Q000378:metabolism; D008970:Molecular Weight; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D010206:Papain / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012697:Serine Endopeptidases / Q000378:metabolism; D012995:Solubility; D013696:Temperature; D010738:Type C Phospholipases / Q000378:metabolism
D001389:Azirines; D003432:Cross-Linking Reagents; D003902:Detergents; D004220:Disulfides; D008081:Liposomes; C033174:3-(trifluoromethyl)-3-(3-iodophenyl)diazirine; D000110:Acetylcholinesterase; D010738:Type C Phospholipases; D012697:Serine Endopeptidases; D019286:Endopeptidase K; D010206:Papain