Background：

Acyl-CoA synthetase that catalyzes the activation of bile acids via formation of bile acid CoA thioesters which is necessary for their subsequent conjugation with glycine or taurine (PubMed:10749848， PubMed:11980911). Both primary bile acids (cholic acid and chenodeoxycholic acid) and secondary bile acids (deoxycholic acid and lithocholic acid) are the principal substrates (PubMed:10749848， PubMed:11980911). Also exhibits acyl CoA synthetase activity that activates very long-chain fatty acids (VLCFAs) by catalyzing the formation of fatty acyl-CoA (PubMed:10479480). In vitro， also activates 3-alpha，7-alpha，12-alpha-trihydroxy-5-beta-cholestanate (THCA)， the C27 precursor of cholic acid deriving from the de novo synthesis from cholesterol (PubMed:11980911). Exhibits long-chain fatty acids (LCFA) transport activity (PubMed:20530735). 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).