Regulation of the activity of microbial kynureninase by transamination of the enzyme-bound coenzyme.

Kynureninase was purified to homogeneity from the extracts of Pseudomonas marginalis and Neurospora crassa. The active kynureninase containing pyridoxal 5'-phosphate transaminates with L-ornithine or L-alanine to form the inactive pyridoxamine 5'-phosphate form of enzyme and delta1-pyrroline-2-carboxylate or pyruvate. This inactive enzyme transaminates with pyruvate to restore the active pyridoxal 5'-phosphate enzyme and L-alanine. The activity of kynureninase is regulated in this manner by transamination of the coenzyme moiety.