Question

Using a figurative, describe how arsenic causes toxity in the tca ( citric acid) cycle

Answer 1

Arsenic is most sensitive to kidney. Chronic arsenic exposure affects the vascular system and causes hypertension and cardiovascular disease. Acute arsenic toxicity may cause cardiomyopathy and hypotension. The most common neurological effect of long-term arsenic toxicity is peripheral neuropathy and the gastrointestinal effects are manifested by toxic hepatitis accompanied by incrrased levels of liver enzymes.

α ketoglutarate dehydrogenase is also a multienzyme complex similar to that of the pyruvate dehydrogenase complex. It lies in the mitochondrial matrix and participates in the TCA cycle. It catalyzes the reaction, conversion of α-ketoglutarate into succinyl-CoA. The α-KG dehydrogenase contains three different enzymes; 1) α-ketoglutarate dehydrogenase (E1), 2) Dihydrolipoyl succinyltransferase (E2), and 3) Dihydrolipoyl dehydrogenase (E3)

The third enzyme dihydro lipoyl dehydrogenase also performs the similar functions to that of the pyruvate dehydrogenase complex oxidizing the dihydrolipoamide. Here again, arsenite and organic arsenicals alter the enzyme activity in the same manner as in the case of pyruvate dehydrogenase complex. As a result, the formation of succinyl-CoA is stopped. This is how Arsenic poisoning halts the TCA cycle and ultimately respiration is ceased.