delta-Aminolevulinic acid formation. Purification and properties of alanine:4,5-dioxovalerate, aminotransferase and isolation of 4,5-dioxovalerate from Clostridium tetanomorphum.

L-Alanine:4,5-dioxovalerate aminotransferase, the enzyme that catalyzes the transamination between alanine and 4,5-dioxovalerate to yield delta-aminolevulinate and pyruvate, has been purified from extracts Clostridium tetanomorphum by acetone precipitation and successive tetanomorphum by acetone precipitation and successive chromatography on Sephadex G-150, hydroxyapatite, Octyl-Sepharose, and SP-Sephadex C-50. The enzyme is pure by the criterion of disc gel electrophoresis with varying polyacrylamide concentrations. It is dimeric, and has an apparent molecular weight of 111,000. Each molecule contains 2 molecules of pyridoxal 5-phosphate. The apparent Km values for 4,5-dioxovalerate and L-alanine are 0.26 and 1.96 mM, respectively. In addition to alanine, glutamate also is an effective amino group donor. The enzyme is inhibited by various keto acids as well as by inhibitors of pyridoxal phosphate-containing enzymes. It was possible to show that 4,5-dioxovalerate is formed by cultures of C. tetanomorphum when grown in the presence of 0.2 M levulinate, an inhibitor of 5-aminolevulinate dehydratase.