Citrate synthase
Citrate synthase (pronunciation: sit-rate sin-thase) is a key enzyme that plays a crucial role in the citric acid cycle, also known as the Krebs cycle or the tricarboxylic acid (TCA) cycle. It catalyzes the condensation of acetyl-CoA and oxaloacetate to form citrate, a process that is fundamental to cellular respiration in virtually all aerobic organisms.
Etymology
The term "citrate synthase" is derived from the name of the molecule it helps to produce, citrate, and the term "synthase," which is used to denote enzymes that catalyze the joining of two molecules without the direct involvement of ATP.
Function
Citrate synthase is the first enzyme in the sequence of reactions that make up the citric acid cycle. It catalyzes the reaction between acetyl-CoA and oxaloacetate to form citrate and coenzyme A (CoA). This reaction is exergonic and irreversible, and it is also highly regulated, making citrate synthase a key control point in the citric acid cycle.
Structure
Citrate synthase is a homodimeric enzyme, meaning it is composed of two identical subunits. Each subunit consists of two domains: a large domain that binds to oxaloacetate and a small domain that binds to acetyl-CoA. The active site of the enzyme, where the reaction takes place, is located in a cleft between these two domains.
Related Terms
See Also
This WikiMD.org article is a stub. You can help make it a full article.