Tsim_1988_Neurosci.Lett_86_245

A 20 S asymmetric (non-globular) form of acetylcholinesterase (AChE, E.C. 3.1.1.7) has been purified from 1-day chick muscle. This form is a hybrid molecule containing both AChE and butyrylcholinesterase (BCHE, E.C. 3.1.1.8) catalytic subunits, linked through a collagenous tail. However, the 20 S hybrid AChE/BCHE could not account for the total enzyme activities of AChE and BCHE in a high-salt/Triton X-100 extract of 1-day chick muscle. By applying AChE- and BCHE-specific monoclonal antibodies for immunoadsorption, homogeneous asymmetric AChE and BCHE forms were also identified in that extract. The homogeneous BCHE accounts for 20% of the total activity of the asymmetric BCHE present and sediments at 17 S. About 6% of the asymmetric AChE present is, likewise, in a homogeneous, instead of the hybrid, form. The 17 S asymmetric BCHE does not react with monoclonal antibodies specific for the collagenous tail of the hybrid 20 S AChE/BCHE molecule, suggesting that the collagenous subunit differs between these two forms.