Chemistry And Mechanism Of Action

The toxicity of a given arsenical is related to the rate of its clearance from the body and therefore to its degree of accumulation in tissues. In general, toxicity increases in the sequence of organic arsenicals <As5+ <As3+ < arsine (AsH3). The organic arsenicals contain arsenic covalently linked to a carbon atom, where arsenic exists in the trivalent or pentavalent state. Arsphenamine contains trivalent arsenic; sodium arsanilate contains arsenic in the pentavalent form. The organic arsenicals usually are excreted more rapidly than are the inorganic forms.

Arsenate (pentavalent) uncouples mitochondrial oxidative phosphorylation by a mechanism whereby arsenate substitutes for inorganic phosphate in the formation of ATP, with subsequent formation of an unstable arsenate ester that is hydrolyzed rapidly. This process is termed arsenolysis.

Trivalent arsenicals, including inorganic arsenite, are regarded primarily as -SH reagents. As such, trivalent arsenicals inhibit many enzymes by reacting with biological ligands containing available -SH groups. The pyruvate dehydrogenase system is especially sensitive to trivalent arsenicals because of their interaction with two -SH groups of lipoic acid to form a stable 6-membered ring.

Was this article helpful?

0 0
Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

Get My Free Ebook


Post a comment