ENZYMATIC FORMATION OF D-KYNURENINE

TL;DRAbstract

A study of the enzyme system responsible for D tryptophan conversion to D-kynurenine showed that a dialyzed supernatant fraction (ca. 20,000g) prepared from homogenates of rabbit intestinal mucosa was capable of converting D-tryptophan in the presence of air, Mg (10 to the -3 power M), adenosine (5 x 10 to the -3 power M), and methylene blue (10 to the -4 power M) to stoichiometric amounts of D-kynurenine. The enzyme activity was evident only in parts of the small intestines corresponding to the terminal 30 per cent of the organ adjacent to the colon. The product was identified as kynurenine by paper chromatography, absorption spectrum, and quantitation of UV optical density measurements in agreement with aromatic amine assay by the Bratton-Marshall method. The D-configuration was assigned primarily on the basis of results of chromatography by the proce dure of Price and Dodge (1956), which distinguishes the D- and L-isomers of kynurenine. Methylene blue appeared essential for the reac

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