The kynureninase of Pseudomonas fluorescens.

Kotake and Nakayama (1) observed the conversion of kynurenine to anthranilic acid and alanine by a mammalian liver extract. Subsequently the enzyme responsible for this reaction in the mammal was partly purified (2,3) and the enzyme, prepared from vitamin Be-deficient animals, was shown to require pyridoxal phosphate for its maximal activity (2). During an investigation of tryptophan metabolism by bacteria, we have shown that a cell-free preparation from tryptophan-adapted pseudomonads metabolizes tryptophan through kynurenine, anthranilic acid, catechol, and cis-cis-muconic acid to P-ketoadipic acid (4). Further study has shown that the enzyme responsible for the degradation of kynurenine catalyzes the same reaction as does mammalian kynureninase. In this report the properties of the bacterial kynureninase are described.