Citrate Assay Kit

Supplementary info

This supplementary information is collated from multiple sources and compiled automatically.

Activity summary

Citrate also known as citric acid is a tricarboxylic acid with the molecular mass of approximately 192.13 g/mol. It is a small molecule that plays a critical role in metabolism. Citrate exists extensively in the mitochondria of eukaryotic cells and in the cytosol. Its high abundance in these locations allows it to participate in various biochemical reactions necessary for cellular energy production. Citrate forms through the condensation of acetyl-CoA and oxaloacetate by the enzyme citrate synthase initiating the tricarboxylic acid (TCA) cycle also known as the Krebs cycle.

Biological function summary

The presence of citrate is essential in the regulation of the TCA cycle where it functions as an important intermediate. Among its functions citrate can inhibit the enzyme phosphofructokinase-1 linking glycolysis and the TCA cycle. This inhibition ensures a balance between the supply of glucose and the demand for ATP. Citrate does not form part of a complex but it interacts with various metabolic enzymes establishing its role as a metabolic regulator. Additionally citrate acts as a substrate for ATP-citrate lyase aiding in the production of acetyl-CoA in the cytosol vital for fatty acid synthesis.

Pathways

Citrate involves itself significantly in the TCA cycle and fatty acid synthesis. The TCA cycle a central component of cellular respiration generates reducing equivalents for oxidative phosphorylation by processing acetyl-CoA. As citrate is part of this pathway it interacts with enzymes such as aconitase and isocitrate dehydrogenase. In fatty acid synthesis citrate serves as an acetyl-CoA donor after being converted by ATP-citrate lyase. This conversion links citrate to important pathways such as lipogenesis and cholesterol synthesis highlighting its diverse roles in cellular metabolism.

Associated diseases and disorders

Citrate has a significant relationship with conditions like cancer and metabolic syndrome. Increased citrate production or its accumulation can occur in cancer cells as tumors often exhibit altered metabolism known as the Warburg effect. In these cases regulatory proteins like hypoxia-inducible factor (HIF) can affect citrate metabolism. In metabolic syndrome altered citrate levels can contribute to disrupted metabolic pathways impacting proteins such as acetyl-CoA carboxylase and fatty acid synthase. Understanding citrate's function in these diseases potentially offers insights into therapeutic targets.