Answer to Question #100994 in Chemistry for Abhishek

Question

Explain the mechanism of action of the enzyme aconitase on citrate in TCA cycle.

Answer 1

Aconitase, an enzyme possessing an iron–sulfur cluster that is sensitive to oxidation, is involved in the regulation of cellular metabolism. There are two isoenzymes of aconitase (Aco) – mitochondrial (mAco) and cytosolic (cAco) ones. The primary role of mAdco is believed to be to control cellular ATP production via regulation of intermediate flux in the Krebs cycle. Reactive oxygen species (ROS) play a central role in regulation of Aco functions. Aconitase has been identified as a protein that undergoes oxidative modification and inactivation in aging and certain oxidative stress-related disorders.

Mitochondrial aconitase converts citrate to isocitrate in the tricarboxylic acid cycle (TCA) and serves as a TCA cycle regulatory enzyme sensitive to oxidation. ROS interacting with aconitase decrease its activity and thereby slow down glucose consumption, respiration and ATP biosynthesis.