PathwayStep1327 PathwayStep1326 PathwayStep1325 (S)-Hydroxybutanoyl-CoA+NAD<=>Acetoacetyl-CoA+NADH+H Crotonoyl-CoA+H2O<=>(S)-3-Hydroxybutanoyl-CoA Butanoyl-CoA+FAD<=>Crotonoyl-CoA+FADH2 Beta oxidation of butanoyl-CoA to acetyl-CoA Authored: Gillespie, ME, 2003-09-19 00:00:00 Edited: Gillespie, ME, 0000-00-00 00:00:00 ISBN0079130356 Reactome Database ID Release 4377352 Reactome, http://www.reactome.org ReactomeREACT_419 The seventh and final pass through the beta-oxidation spiral picks up where the last left off with the saturated fatty acid butanoyl-CoA and at the third step produces acetoacetyl-CoA, which can be used to generate 2 acetyl-CoA molecules or can be turned toward the synthesis of ketone bodies pathway. Four enzymatic steps are required starting with SCAD CoA dehydrogenase (Short Chain) activity, followed by the enoyl-CoA hydratase activity of crotonase, the 3-hydroxyacyl-CoA dehydrogenase activity of the short chain 3-hydroxyacyl-CoA dehydrogenase (SCHAD). The final enzymatic step, creating two acetyl-CoA molecules requires a specific ketoacyl-CoA thiolase, Acetoacetyl-CoA thiolase.