Citric acid (HOOC-CHC(-OH)(-COOH)-CHCOOH) is a key intermediate in the TCA cycle which occurs in mitochondria. It is formed by the addition of oxaloacetate to the acetyl group of acetyl-CoA derived from the glycolytic pathway. Citrate can be transported out of mitochondria and converted back to acetyl CoA for fatty acid synthesis. Citrate is an allosteric modulator of both fatty acid synthesis (acetyl-CoA carboxylase) and glycolysis (phospho- fructokinase). Citrate is widely used industrially in foods, beverages and pharmaceuticals. Citrate metabolism and disposition can vary widely due to sex, age and a variety of other factors. Assay Genie's Citrate Assay Kit provides a simple, sensitive and rapid means of quantifying citrate in a variety of samples. In the assay, citrate is converted to pyruvate via oxaloacetate. The pyruvate is quantified by converting a nearly colorless probe to an intensely colored (570 nm) and fluorescent (Ex/Em, 535/587 nm) product. The Citrate Assay Kit can detect 0.1 to 10 nmoles (~2 µM-10 mM) of citrate in a variety of samples.

Figure 1: Citrate standard curve generated using this kit protocol