Butyryl-CoA

Butyryl-coenzyme A (or butyryl-CoA) is the coenzyme A-activated form of butyric acid.
It is acted upon by butyryl-CoA dehydrogenase.
It is an intermediary compound of ABE fermentation
Butyryl-CoA is also converted from Crotonyl-CoA. This occurs when FADH- transfers a hydride to crotonyl-CoA. It is essential in reducing ferredoxins in anaerobic bacteria and archaea so that electron transport phosphorylation and substrate level phosphorylation can occur with increased efficiency.
Butyryl-COA dehydrogenase Oxidation-Reduction reaction consists of 2 electron transfer with 1 proton exchange. Ideally, this will occur between pH 5.5 and 7 for optimal reaction. In this range is where the enzyme is most stable.
From Redox data, Butyryl-COA dehydrogenase shows little to no activity at pH higher than 7.0. This is important as Enzyme midpoint potential is at pH 7.0 and at 25 degrees C. Therefore, changes above from this value will denature the enzyme.