The anaerobic degradation of 5-aminovalerate to valerate, acetate, propionate, and ammonia by Clostridium aminovalericum was shown to involve the following intermediates: glutaric semialdehyde, 5-hydroxyvalerate, 5-hydroxyvaleryl-CoA, 4-pentenoyl-CoA, 2,4-pentadienoyl-CoA, trans-2-pentenoyl-CoA, L-3-hydroxyvaleryl-CoA, 3-ketovaleryl-CoA, acetyl- and propionyl-CoA and the corresponding acylphosphates, valeryl-CoA, and possibly 3-pentenoyl-CoA. With exception of the enzyme presumably reducing 2,4-pentadienoyl-CoA to 3-pentenoyl-CoA, enzymes catalyzing the formation and utilization of the above intermediates were demonstrated in extracts. Trans-2-pentenoyl-CoA was shown to be the immediate precursor of valeryl-CoA. The reduction of 2-pentenoyl-CoA was found to be coupled to the oxidation of 4-pentenoyl-CoA to 2,4-pentadienoyl-CoA. Several enzymes catalyzing the above reactions were partially purified and some of their properties determined. A high pressure liquid chromatography method of identifying and estimating most of the above mentioned CoA thiolesters was developed.