title: Cholinesterase activity in the plaques, tangles and angiopathy of Alzheimer's disease does not emanate from amyloid.
abstract: Previous histochemical observations in our laboratory have demonstrated the presence of butyrylcholinesterase and an enzymatically altered form of acetylcholinesterase activity in the plaques, tangles and amyloid-containing vessels of Alzheimer's disease. These findings suggested possible interactions between amyloid and cholinesterases. In this study we employed a cholinesterase biochemical assay to determine whether the amyloid precursor protein either had cholinesterase activity itself or influenced the enzymatic activity of cholinesterases. None of the three amyloid precursor sequences used (695, 751, 770, up to 16 micrograms/ml) exhibited any acetylcholinesterase or butyrylcholinesterase activity that could be detected by our method. In addition, none of the amyloid precursor proteins influenced the enzymatic activity of purified acetylcholinesterase or butyrylcholinesterase in a specific manner. It is therefore quite unlikely that amyloid can, by itself, account for the intense cholinesterase activity associated with the pathological lesions of AD.
authors.affiliation: Bullard Laboratory, Department of Neurology, Harvard Medical School, Boston, MA.
authors.forename: C
authors.initials: C
authors.lastname: Geula
authors.forename: B D
authors.initials: BD
authors.lastname: Greenberg
authors.forename: M M
authors.initials: MM
authors.lastname: Mesulam
mesh_terms: D000544:Alzheimer Disease / Q000201:enzymology* / Q000473:pathology; D016564:Amyloid beta-Protein Precursor / Q000737:chemistry / Q000378:metabolism*; D002091:Butyrylcholinesterase / Q000378:metabolism; D016657:Cerebral Amyloid Angiopathy / Q000201:enzymology* / Q000473:pathology; D002802:Cholinesterases / Q000378:metabolism*; D006651:Histocytochemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016874:Neurofibrillary Tangles / Q000201:enzymology* / Q000473:pathology; D014361:Trypsin Inhibitors / Q000494:pharmacology
chemical_list: D016564:Amyloid beta-Protein Precursor; D014361:Trypsin Inhibitors; D002091:Butyrylcholinesterase; D002802:Cholinesterases