acetylcholinesterase

…rapidly destroyed by the enzyme acetylcholinesterase and thus is effective only briefly. Inhibitors of the enzyme (drugs known as anticholinesterases) prolong the lifetime of acetylcholine. Such agents include physostigmine and neostigmine, which are used to help augment muscle contraction in certain gastrointestinal conditions and in myasthenia gravis. Other acetylcholinesterases have…

…broken down by the enzyme acetylcholinesterase, which is anchored in the basement membrane, or diffuses out of the primary cleft, thus preventing constant stimulation of acetylcholine receptors. Drugs that inactivate acetylcholinesterase and thereby prolong the presence of acetylcholine in the cleft can lead to repetitive firing of the muscle cell…

…the enzyme for its breakdown, acetylcholinesterase, are also found in motor neuron regions of the spinal cord.

Acetylcholinesterase is used as a specific example in the sequence described below. The two substrates (S₁ and S₂) for acetylcholinesterase are acetylcholine (i.e., B―X) and water (Y). After acetylcholine (B―X) binds to the enzyme surface, a chemical bond forms between the acetyl moiety (B) of…

…receptors, or (3) the enzyme acetylcholinesterase (which normally inactivates acetylcholine to terminate muscle fibre contraction).

…rather, it inhibits an enzyme, acetylcholinesterase, which normally degrades acetylcholine, the neurotransmitter of the parasympathetic nervous system. Inhibition of this enzyme leads to an exaggeration of the actions of the parasympathetic nervous system, including sweating, secretion of saliva, adjustment of pupil size, and defecation. The end results are increased perspiration,…