Über die Umwandlung der 3-Hydroxy-anthranilsäure in Chinolinsäure und Nicotinsäure im tierischen Organismus

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Abstract
A mammalian liver enzyme is described which cleaves 3-hydroxy-anthranilic acid oxidatively at 0[degree]with the uptake of 1 mole of O2. The reaction product is characterized by means of its UV spectrum and has 2 typical maxima at 275 mu and 360 m[mu]. It is shown that under the conditions selected quinolinic acid is not formed initially. The primary oxidation product can be converted quantitatively into quinolinic acid in a non-enzymatic reaction, viz. by heating to 100[degree]. An aldehyde group can be demonstrated in the primary oxidation product by means of the reaction with 2.4-dinitrophenyl-hydrazine. The reversible shift of the absorption maximum of the primary oxidation product at 360 mu by acidification and neutralization points to the presence of an amino group. The magnitude of the molar extinction and the position of the longwave maximum in the UV absorption spectrum indicate that 2 conjugated double bonds are situated in conjugation to the amino and aldehyde groups. It is concluded that the first enzymatic oxidation product of 3-hydroxy-anthranilic acid which can be demonstrated is, in all probability, l-amino-4-formyl-buta-1.3-dien-dicarboxylic acid.