ACS gene family

Genes in the ACS gene family provide instructions for making enzymes called acyl-coenzyme A (or acyl-CoA) synthetases and other related enzymes. Acyl-CoA synthetases perform a chemical reaction called a thioesterification that attaches a coenzyme A (CoA) molecule to fatty acids, which are the building blocks used to make fats (lipids). Fatty acids are a major source of energy for the heart and muscles. During periods without food (fasting), fatty acids are also an important energy source for the liver and other tissues. The reaction performed by acyl-CoA synthetases is the first step in the breakdown of fatty acids for energy. Some acyl-CoA synthetases are also involved in the transport of fatty acids into cells, where they are broken down.

Related enzymes produced from genes in the ACS family perform a thioesterification reaction on other types of acids. For example, the enzyme produced from the ACSF3 gene attaches CoA to the organic acids malonic acid and methylmalonic acid, converting them to malonyl-CoA and methylmalonyl-CoA, respectively. These reactions are important for the formation (synthesis), rather than the breakdown, of fatty acids, specifically in cell structures called mitochondria. Mitochondria convert the energy from food into a form that cells can use, and fatty acid synthesis in these structures is thought to be important for their proper functioning. Mutations in the ACSF3 gene cause a condition known as combined malonic and methylmalonic aciduria (CMAMMA), which leads to high levels of malonic acid and methylmalonic acid in the body and causes developmental and neurological problems.