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Updated: Jul 5, 2026

Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase
Published on: November 23, 2016
The level of aryl acylamidase activity displayed by human butyrylcholinesterase depends on its molecular distribution
M F Montenegro1, M T Moral-Naranjo, M Páez de la Cadena
1Department of Biochemistry and Molecular Biology-A, University of Murcia, Murcia, Spain.
Abstract:
Butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE) display both esterase and aryl acylamidase (AAA) activities. Their AAA activity can be measured using o-nitroacetanilide (ONA). In human samples depleted of acetylcholinesterase, we noticed that the ratio of amidase to esterase activities varied depending on the source, despite both activities being due to BuChE. Searching for an explanation, we compared the activities of BuChE molecular forms in samples of human colon, kidney and serum, and observed that BuChE monomers (G(1)) hydrolyzed o-nitroacetanilide much faster than tetramers (G(4)). This fact suggested that association might cause differences in the AAA site between single and polymerized subunits. This and other post-translational modifications in BuChE subunits probably determine their level of AAA activity. The higher amidase activity of monomers could justify the presence of single BuChE subunits in cells as a way to preserve the AAA activity of BuChE, which could be lost by oligomerization.
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