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Solubilization of Membrane‐Bound Acetyicholinesterase by a Phosphatidylinositol‐Specific Phospholipase C
Author(s) -
Futerman Anthony H.,
Low Martin G.,
Michaelson Daniel M.,
Silman Israel
Publication year - 1985
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1985.tb07217.x
Subject(s) - torpedo , phospholipase c , acetylcholinesterase , biochemistry , chemistry , synaptosome , protein subunit , phosphatidylinositol , phospholipase , membrane , enzyme , acetylcholine receptor , receptor , kinase , gene
Phosphatidylinositol‐specific phospholipase C (PIPLC) quantitatively solubilizes acetylcholinesterase (AChE) from purified synaptic plasma membranes and intact synaptosomes of Torpedo ocellata electric organ. The solubilized AChE migrates as a single peak of sedimentation coefficient 7.OS upon sucrose gradient centrifugation, corresponding to a subunit dimer. The catalytic subunit polypeptide of AChE is the only polypeptide detectably of soubilized by PIPLC. This selective removal of AChE does not affect the amount of acetylcholine released from intact synaptosomes upon K + depolarization. PIPLC also quantitatively solubilizes AChE from the surface of intact bovine and rat erythrocytes, but only partially solubilizes AChE from human and mouse erythrocytes. The AChE released from rat and human erythrocytes by PIPLC migrates as a ∼ 7S species on sucrose gradients, corresponding to a catalytic subunit dimer. PIPLC does not solubilize particulate AChE from any of the brain regions examined of four mammalian species. Several other phospholipases tested, including a nonspecific phospholipase C from Clostridium welchii , fail to solubilize AChE from Torpedo synaptic plasma membranes, rat erythrocytes, or rat striatum.