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Organophosphates


An organophosphate (sometimes abbreviated OP) or phosphate ester is the general name for esters of phosphoric acid. Organophosphates are the basis of many insecticides, herbicides, and nerve agents. The United States Environmental Protection Agency lists organophosphates as very highly acutely toxic to bees, wildlife, and humans. Recent studies suggest a possible link to adverse effects in the neurobehavioral development of fetuses and children, even at very low levels of exposure. Organophosphates are widely used as solvents, plasticizers, and EP additives.

Organophosphates are widely employed both in natural and synthetic applications because of the ease with which organic groups can be linked together.

The phosphate esters bearing OH groups are acidic and partially deprotonated in aqueous solution. For example, DNA and RNA are polymers of the type [PO2(OR)(OR')]n. Polyphosphates also form esters; an important example of an ester of a polyphosphate is ATP, which is the monoester of triphosphoric acid (H5P3O10).

Alcohols can be detached from phosphate esters by hydrolysis, which is the reverse of the above reactions. For this reason, phosphate esters are common carriers of organic groups in biosynthesis.

The word "organophosphates", when appearing in communications (e.g., from the press or the government), in areas such as agriculture, the environment, and human and animal health, very often refers to a group of insecticides (pesticides) that act on the enzyme acetylcholinesterase (see also carbamates). Today, organophosphates make up about 50% of the killing agents in chemical pesticides.

Organophosphate pesticides (OPPs), like some nerve agents, inhibit this neuromuscular enzyme, which is broadly essential for normal function in insects, but also in humans and many other animals. OPPs affect this enzyme in varied ways, a principle one being through irreversible covalent inhibition, and so create potentials for poisoning that vary in degree. The brain sends out neurotransmitters to the nerve endings in the body; organophosphates disrupt this process from occurring.This chemical, organophosphate works by disrupting the enzyme, acetylcholinesterase. Acetylcholinesterase break down the acetylcholine neurotransmitter, which sends out signals to other nerve endings in the body. Without these neurotransmitters from the brain, the nerves in the human body cannot function properly.


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