Figure 2.

Graphical representation of the butyrate synthesis pathways. In the butyrate kinase pathway, two molecules of acetyl CoA combine to form butyryl CoA. Subsequently, phosphotransbutyrylase catalyzes the conversion of butyryl CoA into butyryl phosphate. Finally, butyrate is generated from butyryl phosphate through the activity of butyrate kinase. The butyryl-CoA: acetate CoA-transferase pathway converts butyryl CoA and acetate by a series of β oxidation enzymatic reactions into butyrate and acetyl CoA [34,35].