This article is missing information about EC 6.3.4.9, 6.3.4.11, 6.3.4.15. Please expand the article to include this information. Further details may exist on the talk page.(November 2020)
Holocarboxylase synthetase (biotin—(propionyl-Coenzyme A-carboxylase (ATP-hydrolysing)) ligase)), also known as protein—biotin ligase, is a family of enzymes (EC6.3.4.10). This enzyme is important for the effective use of biotin, a B vitamin found in foods such as liver, egg yolks, and milk. In many of the body's tissues, holocarboxylase synthetase activates other specific enzymes (called biotin-dependent carboxylases) by attaching biotin to them. These carboxylases are involved in many critical cellular functions, including the production and breakdown of proteins, fats, and carbohydrates.
Holocarboxylase synthetase may also play a role in regulating the activity of genes. In the nucleus, the enzyme likely attaches biotin molecules to histones, which are structural proteins that bind to DNA and give chromosomes their shape. Changing the shape of histones may help determine whether certain genes are turned on or off; however, it is not known how adding biotin affects gene regulation.
The HLCS gene is located on the long (q) arm of chromosome 21 at position 22.1, from base pair 37,045,059 to base pair 37,284,372.