Cholinesterase

Cholinesterase (ChE) is a generic term used for a family of related enzymes that hydrolyze choline esters at a faster rate than other esters under optimal conditions.

The major function of ChE is to terminate the action of acetylcholine (ACh) at cholinergic nerve endings in synapses or in effector organs. Drugs that inhibit ChE's, the anticholinesterases (Anti-ChE) cause the accumulation of ACh at the receptor sites producing effects due to excessive stimulation. Due to the extensive distribution of the cholinergic nerve endings in the human body (human, animal or insect), a vast array of anti-ChE products have been developed for use in residential applications (lawn and garden), the agricultural industry, and as chemical warfare agents. Thus due to the clinical and toxicological significance of ChE, it is one of the most intensely investigated enzymes in the toxicologist's laboratory.

Types of Cholinesterase

There are two types of ChE in the human body, with several variations and a confusing set of names. One type of ChE is Acetylcholinesterase (AChE) also known as true, specific, genuine or type 1 ChE. This enzyme is found in erythrocytes, nerve endings, lungs, spleen and in the fray matter of brain. This enzyme is a membrane-bound glycoprotein and exists in several molecular forms.The other subgroup, Pseudo-cholinesterase (PChE) also known as plasma, serum, benzoyl, false, butyryl, nonspecific, or type II ChE. PCh Exists in plasma and has more than eleven isoenzyme variants. PChE is also present in liver, smooth muscle, intestines, pancreas, heart and white matter of brain.

Images to click and see:

The 3D Simulation of ACh and AChE