The enzyme, characterized from the gut bacterium Clostridium scindens, catalyses the last step in bile acid 7alpha-dehydroxylation, the removal of the CoA moiety from the products. By using a transferase rather than hydrolase, the bacteria conserve the thioester bond energy, saving ATP molecules. Clostridium scindens possesses two forms of the enzyme, encoded by the baiF and baiK genes. While the enzymes have a broad acceptor specificity and can use allocholate, ursodeoxycholate, and beta-muricholate, the donor specificity is more strict. BaiF acts on lithocholoyl-CoA and deoxycholoyl-CoA, and BaiK acts only on the latter.
History
EC 2.8.3.25 created 2005 as EC 3.1.2.26, transferred 2016 to EC 2.8.3.25
Identification and characterization of two bile acid coenzyme A transferases from Clostridium scindens, a bile acid 7alpha-dehydroxylating intestinal bacterium.
