Lewisite (L) (A-243) is an organoarsenic compound. It was once manufactured in the U.S., Japan, Germany[2] and the Soviet Union[3] for use as a chemical weapon, acting as a vesicant (blister agent) and lung irritant. Although the substance is colorless and odorless in its pure form, impure samples of lewisite are a yellow, brown, violet-black, green, or amber oily liquid with a distinctive odor that has been described as similar to geraniums.[4][5][6]

Apart from deliberately injuring and killing people, lewisite has no commercial, industrial, or scientific applications.[7] In a 1959 paper regarding the development of a batch process for lewisite synthesis, Gordon Jarman of the United States Army Chemical Warfare Laboratories said:

The manufacture can be one of the easiest and most economical in the metal-organic field, and it is regretted that no one has ever found any use for the compound. It is a pity to waste such a neat process.[7]

Lewisite is a suicide inhibitor of the E3 component of pyruvate dehydrogenase. As an efficient method to produce ATP, pyruvate dehydrogenase is involved in the conversion of pyruvate to acetyl-CoA. The latter subsequently enters the TCA cycle. Peripheral nervous system pathology usually arises from Lewisite exposure as the nervous system essentially relies on glucose as its only catabolic fuel.[10]

In biochemistry, suicide inhibition, also known as suicide inactivation or mechanism-based inhibition, is an irreversible form of enzyme inhibition that occurs when an enzyme binds a substrate analog and forms an irreversible complex with it through a covalent bond during the normal catalysis reaction. The inhibitor binds to the active site where it is modified by the enzyme to produce a reactive group that reacts irreversibly to form a stable inhibitor-enzyme complex

Pyruvate dehydrogenase is usually encountered as a component, referred to as E1, of the pyruvate dehydrogenase complex (PDC). PDC consists of other enzymes, referred to as E2 and E3. Collectively E1-E3 transform pyruvate, NAD+, coenzyme A into acetyl-CoA, CO2, and NADH. The conversion is crucial because acetyl-CoA may then be used in the citric acid cycle to carry out cellular respiration.[2]

it stops your cells from performing cellular respiration! by permanently breaking the enzymes! so fucked!