May mediate the import of long-chain fatty acids (LCFA) by facilitating their transport across cell membranes (, ). Also catalyzes the ATP-dependent formation of fatty acyl-CoA using LCFA and very-long-chain fatty acids (VLCFA) as substrates . Mainly functions as a bile acyl-CoA synthetase catalyzing the activation of bile acids via ATP-dependent formation of bile acid CoA thioesters which is necessary for their subsequent conjugation with glycine or taurine (, ). Both primary bile acids (cholic acid and chenodeoxycholic acid) and secondary bile acids (deoxycholic acid and lithocholic acid) are the principal substrates (, ). In vitro, activates 3-alpha,7-alpha,12-alpha-trihydroxy-5-beta-cholestanate ((25R)-3alpha,7alpha,12alpha-trihydroxy-5beta-cholestan-26-oate or THCA), the C27 precursor of cholic acid deriving from the de novo synthesis from cholesterol . Plays an important role in hepatic fatty acid uptake and bile acid reconjugation and recycling but not in de novo synthesis of bile acids (By similarity).
Subcellular locations: Endoplasmic reticulum membrane, Microsome, Cell membrane
Predominantly expressed in liver.