ON THE FORMATION OF GENTISIC ACID FROM HOMOGENTISIC ACID BY THE LIVER EXTRACT*

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Abstract
Homogentisic acid was proved to be converted into gentisic acid and, in part, into acetoacetic acid by incubation at pH 7.2 with a phosphate buffer (0.1[image], pH 7.2)-extract of rabbit liver, provided 10-3 [image] nitroso-R salt was present. The rate of O2-uptake was decreased by the presence of nitroso-R salt, but total amount of 02 taken up approximated that in absence of nitroso-R salt (2-2.5 atoms./mol. homogentisic acid decomposed). alpha, alpha''-Dipyridyl was strongly inhibitory to homogentisic acid, oxidation but it showed no effect in presence of nitroso-R salt. From the reaction mixture (large scale), crystalline -gentisic acid was prepared with the use of paper chromatography, which followed ether extraction. From the urine of rabbit (1.5 kg) force-fed tyrosine (2.0 g) and simultaneously receiving an intraperitoneal injection of nitroso- R salt (200 mg), the spots of homogentisic (Rf 0.80), and gentisic acids (Rf 0.86-0.88) together with an unidentified spot (Rf 0.90) were observed on a paper chromatogram developed by a butaneol-glyacetic acid-water mixture (4:1:5). None of these spots was detectable from the urine after administration of tyrosine alone.

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