Veterinary Taxicology

MECHANISM OF TOXICITY

• Arsenic reacts with the sulphydryl group of lipoic acid.
• Lipoic acid is an essential co-factor for the enzymatic decarboxylation of keto acids such as pyruvate, ketoglutarate and ketobutyrate.
• By inactivating lipoic acid, arsenic inhibits formation of acetyl, succinyl and propionyl coenzymes A.
• So there is inhibition or slowing of glycolysis and of the citric acid cycle.
• Arsenic also inactivates sulphydryl groups of oxidative enzymes and glutathione.
• Pentavalent arsenate is a well-known un-coupler of mitochondrial oxidative phosphorylation.