Battie C, Verity M A
J Neurochem. 1981 Mar;36(3):1308-10. doi: 10.1111/j.1471-4159.1981.tb01737.x.
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.
犬尿氨酸-3-羟化酶是色氨酸降解途径中的一种酶，存在于新生大鼠的大脑皮层中，其对L-犬尿氨酸的米氏常数与肝脏中的酶相近。通过Ficoll-蔗糖梯度离心从新生大鼠大脑皮层分离得到的线粒体组分中这种酶含量丰富，突触体组分中也有一些活性，这可能是由于突触体的线粒体含量，因为另一种线粒体酶细胞色素c氧化酶在梯度中的分布相似。与8日龄大鼠的组分相比，从14日龄大鼠分离得到的突触体组分中，犬尿氨酸羟化酶以及另一种线粒体酶单胺氧化酶的比活性增加。出生当天诱导的甲状腺功能减退导致从14日龄大鼠分离得到的突触体组分中犬尿氨酸羟化酶和单胺氧化酶的活性增加。
