Citrate is an important intermediate in the citric acid cycle which occurs in mitochondria. Citrate is produced by the addition of oxaloacetate to the acetyl group of acetyl-CoA derived from the glycolytic pathway. Citrate can also be transported out of mitochondria and transformed to acetyl CoA for fatty acid synthesis. Citrate is an allosteric modulator of both phospho-fructokinase (glycolysis) and acetyl-CoA carboxylase (fatty acid synthesis). Citrate metabolism and disposition is various due to age, sex and a variety of other factors. The Citrate Colorimetric/Fluorometric Assay Kit provides a sensitive, simple, fast and convenient way for detection of citrate levels in various biological samples based on colorimetric and fluorometric method. In the assay, citrate is converted to pyruvate via oxaloacetate. The formed pyruvate is quantified via converting a nearly colorless probe to an intensely fluorescent (Ex/Em, 535/587 nm) and colored (570 nm) product. The kit can detect 0.1 to 10 nmoles (approx. 2 µM-10 mM) citrate in various samples.