Butyrate—CoA ligase

Butyrate—CoA ligase, also known as xenobiotic/medium-chain fatty acid-ligase (XM-ligase), is an enzyme that catalyzes the chemical reaction:
 * ATP + a carboxylic acid + CoA $$\rightleftharpoons$$ AMP + diphosphate + an acyl-CoA

The 3 substrates of this enzyme are ATP, carboxylic acid, and CoA, whereas its 3 products are AMP, diphosphate, and acyl-CoA.

This enzyme belongs to the family of ligases, specifically those forming carbon-sulfur bonds as acid-thiol ligases. This enzyme participates in the glycine conjugation of xenobiotics and butanoate metabolism.

Nomenclature
The systematic name of this enzyme class is butanoate:CoA ligase (AMP-forming). Other names in common use include:
 * butyryl-CoA synthetase, fatty acid thiokinase (medium chain),
 * acyl-activating enzyme, fatty acid elongate,
 * fatty acid activating enzyme,
 * fatty acyl coenzyme A synthetase,
 * medium chain acyl-CoA synthetase,
 * butyryl-coenzyme A synthetase,
 * L-(+)-3-hydroxybutyryl CoA ligase,
 * xenobiotic/medium-chain fatty acid ligase, and
 * short-chain acyl-CoA synthetase.

Human proteins containing this domain

 * ACSM1
 * ACSM2A
 * ACSM2B
 * ACSM3
 * ACSM4
 * ACSM5
 * ACSM6