Presence of kynurenine hydroxylase in developing rat brain.
Kynurenine-3-hydroxylase, an enzyme that is part of the degradative pathway for tryptophan, was present in the cerebral cortex of neonatal rats and exhibited a Km for L-kynurenine close to that of the liver enzyme. This enzyme was enriched in mitochondrial fractions isolated from cerebral cortices of neonatal rats by Ficoll--sucrose gradient centrifugation, with some activity also present in synaptosomal fractions probably due to the mitochondrial content of synaptosomes since cytochrome c oxidase, another mitochondrial enzyme, had a similar distribution in the gradient. Kynurenine hydroxylase as well as monoamine oxidase, another mitochondrial enzyme, had increased specific activities in synaptosomal fractions isolated from 14-day-old rats compared to fractions from 8-day-old rats. Hypothyroidism, induced on the day of birth, resulted in increased activities of kynurenine hydroxylase and monoamine oxidase in synaptosomal fractions isolated from 14-day-old rats.
D000818:Animals; D001921:Brain / Q000201:enzymology* / Q000254:growth & development; D003576:Electron Transport Complex IV / Q000378:metabolism; D007037:Hypothyroidism / Q000201:enzymology; D050601:Kynurenine 3-Monooxygenase; D008928:Mitochondria / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D008995:Monoamine Oxidase / Q000378:metabolism; D051381:Rats; D013574:Synaptosomes / Q000201:enzymology
D006899:Mixed Function Oxygenases; D050601:Kynurenine 3-Monooxygenase; D008995:Monoamine Oxidase; D003576:Electron Transport Complex IV