Brimijoin_1988_J.Neurochem_51_1227

Enzyme-linked immunosorbent assays for acetylcholinesterase (AChE) and for butyrylcholinesterase (BCHE) were markedly more specific than conventional assays using selective enzyme inhibitors. The new assays were used with blood and brain samples containing traces of one enzyme dominated by large amounts of the other. The results showed that human plasma does contain AChE (8 ng/ml), even though its major cholinesterase is BCHE (3,300 ng/ml). BCHE immunoreactivity was not detected in human red blood cells but occurred in all brain regions. The cerebellum was the richest region tested (540 ng of BCHE/g of tissue), whereas the cerebral cortex was the poorest (240 ng of BCHE/g). However, because of the small local AChE content (99 ng/g), BCHE was the major cortical cholinesterase. The picture was reversed in the putamen, where BCHE immunoreactivity (340 ng/g) was far outweighed by that of AChE (6,100 ng/g).