ON THE FORMATION OF GENTISIC ACID FROM HOMOGENTISIC ACID. III

抄録

1. In the intact rabbit and its liver extract, in the presence of nitroso-R salt, the formation of GA from HGA, GAL, DPGCA and DPGOA was demonstrated respectively. In the case of HGA four spots beside that of substrate were found on the paperchromatogram which were identified as GA, GAL, DPGCA and DPGOA. The R_f 0.77 compound was remained unidentified, though it could be metabolized to GA.
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FIG 1. Paperchromatogram of the reaction mixture of HPAA by liver extract.
(1) GA
(2) SA
(3) HPAA
(4) HPAA 60 μM, liver extract 20ml.; pH 7.2, time 3 hrs.
(5) (4) plus nitroso-R salt:final concentration 10^-3M;
Solvent:
isopropanol: NH₄OH: water=8:1:1
Notice: The spots corresponding to GA, SA and HPAA respectively are easily distinguished by their behavior to the ultraviolet-light. GA shows bluish-white fluorescence, SA greenish-white to the ultraviolet-light, while HPAA absorbs the ultraviolet-light.
2. Among 10 metalcatchers tested, nitroso-R salt, oxine and o-phenanthroline were effective on the formation of GA, and seem to block the different point of this pathway individually. R-acid, G-acid, Schaeffer's acid and N-W-acid were proved to be inert.
3. Since the side chain of HPAA was not abbreviated to form SA, 2, 5-dihydroxy group of HGA is essential for the abbreviation of its acetate rest in the organism.
The authors are indebted to Dr. T. Sakan for synthesizing of GAL, DPGCA and DPGOA.