T Noguchi

The identification of 4, 6-quinolinediol and 4,8-quinolinediol in the urine of hens.

Abstract 1. 1. A study was carried out on the urinary excretion of quinoline derivatives derived from tryptophan in hens under normal and tryptophan-loading conditions. 2. 2. The administration of tryptophan resulted in the occurence of 4,6-quinolinediol, 4,8-quinolinediol, 6-hydroxykynurenic acid, kynurenic acid, xanthurenic acid and some other unidentified compounds, although no quinoline derivative was detected in normal urine. 3. 3. Hitherto 4,6-quinolinediol has not been shown to be a natural product in any species. This would, therefore, seem to be the first demonstration of the occurence of this quinoline derivative. 4. 4. A compound identified as 4,8-quinolinediol was found in hens urine. This would appear to be the first example of the excretion of a quinolinediol by an animal following the ingestion of a normal nutrient. 5. 5. The possible routes of formation of 4,6-quinolinediol and 4,8-quinolinediol are discussed.

The isolation and identification of 5-hydroxy-L-kynurenine from the urine of hens.

Abstract 1. 1. By a composition of column and paper chromatography a new tryptophan metabolite was isolated in crystalline form from the urine of hens after continuous ingestion of tryptophan. 2. 2. The compound was identified as 5-hydroxy- l -kynurenine from the chemical and physical properties. 3. 3. Hitherto 5-hydroxy- l -kynurenine has not been found as a natural product in any species. 4. 4. The possible biosynthetic routes of the new product are discussed.

Gas chromatographic analysis of tryptophan metabolites

Abstract A procedure was developed for preparing the derivatives of tryptophan metabolites, which were classified into three groups; (A) kynurenine and its related compounds; (B) 2-aminoacetophenone and its related compounds; and (C) anthranilic acid and its related compounds. Groups A and B were converted to methoxy trifluoroacetylamino acetophenones and group C to methyl methoxy trifluoroacetylamino anthranilates. Each of these derivatives has proved to be useful for gas chromatographic separations using Apiezon grease L on Celite 545 SK with isothermal temperature.

Tryptophan-5-hydroxylase in rat small intestine

Abstract An enzyme system that catalyzes the conversion of L-tryptophan to 5-hydroxy-L-tryptophan was studied in the 5,000 × g supernatant fraction of 0.25 M sucrose homogenate of the rat small intestine. The reaction proceeded in the presence of ascorbic acid under aerobic conditions. The enzyme did not require cupric ion.

Purification, characterization and identification of aromatic 2-oxo acid reductase.

Abstract Aromatic 2-oxo acid reductase was purified to homogeneity from the cytosol of dog heart. The purified enzyme utilized various 2-oxo acids as substrates in the following order of activity: oxaloacetate > 3,5-diiodo-4-hydroxyphenylpyruvate > indolepyruvate > phenylpyruvate. Little or no activity was detected with glyoxylate, pyruvate, hydroxypyruvate, 2-oxoglutarate and 2-oxoadipate. NADH was active as coenzyme but not NADPH. The enzyme has an isoelectric point of 5.4 and is probably composed of two identical subunits with a molecular weight of approx. 40000. Evidence was presented that aromatic 2-oxo acid reductase is identical with one of the cytosol malate dehydrogenase isoenzymes. The enzyme was also found in the brain, kidney and liver of dog.