Examination of cross-antigenicity of acetylcholinesterase and butyrylcholinesterase using anti-acetylcholinesterase antibodies.

Acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) share a high degree of homology and overlap in several biochemical properties. This study aimed to compare and contrast the antigenic reactivity of AChE and BuChE with several polyclonal antibodies. We have performed a detailed analysis of AChE and BuChE enzymatic activities with different substrates and different inhibitors. Immunoassays conducted with polyclonal amino-terminus-specific anti-AChE antibodies were selective for mouse and electric eel AChE (EEAChE). Polyclonal carboxy-terminus-specific anti-AChE antibodies reacted with EEAChE and human BuChE, indicating an unexpected cross-reactivity. Polyclonal antisera raised against the whole AChE protein cross-reacted with horse BuChE, but not human BuChE. These data demonstrate that AChE and BuChE are immunologically similar.