DISTRIBUTION OF CHOLINESTERASE IN NORMAL HUMAN MUSCLE

Abstract

The intracellular distribution of acetylcholinesterase and butyrylcholinesterase in biopsied human rectus abdominis and quadriceps femoris muscles was investigated. Differential ultracentrifugal fractionation showed that the highest specific activity of acetylcholinesterase was associated with the microsomal fraction, this enzyme being concentrated 19-fold compared to the original homogenate. The highest specific activity of butyrylcholinesterase was found in the non-particulate fraction. The mitochondrial fraction showed the lowest specific cholinesterase activity. Wide variation of cholinesterase activity was found in various autopsied muscles, the highest being oculomotor muscle and the lowest cardiac ventricular muscle. About 90% of the cholinesterase activity of skeletal muscle was due to acetylcholinesterase and 10% to butyrylcholinesterase.