Saito K, Quearry B J, Saito M, Nowak T S, Markey S P, Heyes M P
Section on Analytical Biochemistry, National Institute of Mental Health, Bethesda, Maryland 20892.
Arch Biochem Biophys. 1993 Nov 15;307(1):104-9. doi: 10.1006/abbi.1993.1567.
We have developed a rapid and highly sensitive assay for brain kynurenine 3-hydroxylase activity. The present study determined some characteristics and species differences of kynurenine 3-hydroxylase activity in brain and evaluated the response of this enzyme to cerebral ischemia. The kynurenine 3-hydroxylase assay is based on the conversion of L-kynurenine to 3-hydroxykynurenine in vitro and the quantification of 3-hydroxykynurenine by high-performance liquid chromatography. Kynurenine 3-hydroxylase activity was detected in human, macaque, rat, mouse, and gerbil brain. Regional gerbil brain activities ranged from 20 to 50 nmol/g/h, while kynurenine 3-hydroxylase activities in other species were one order of magnitude lower. Kynurenine 3-hydroxylase was also detected in lung, kidney, spleen, intestine, and liver of gerbils, with activities larger than in brain. Delayed increases in the activity of kynurenine 3-hydroxylase occur in several brain regions following transient ischemia in gerbils. These changes are particularly marked in regions that showed the most extensive brain damage (hippocampus and striatum). Kynurenine 3-hydroxylase may have an important role in determining the flux of kynurenine in brain.
我们已经开发出一种快速且高度灵敏的检测脑犬尿氨酸3-羟化酶活性的方法。本研究确定了脑内犬尿氨酸3-羟化酶活性的一些特征和物种差异，并评估了该酶对脑缺血的反应。犬尿氨酸3-羟化酶检测基于体外将L-犬尿氨酸转化为3-羟基犬尿氨酸，并通过高效液相色谱法定量3-羟基犬尿氨酸。在人、猕猴、大鼠、小鼠和沙鼠的脑中检测到了犬尿氨酸3-羟化酶活性。沙鼠脑内不同区域的活性范围为20至50 nmol/g/h，而其他物种的犬尿氨酸3-羟化酶活性则低一个数量级。在沙鼠的肺、肾、脾、肠和肝中也检测到了犬尿氨酸3-羟化酶，其活性高于脑内。沙鼠短暂性脑缺血后，几个脑区的犬尿氨酸3-羟化酶活性会出现延迟增加。这些变化在脑损伤最广泛的区域（海马体和纹状体）尤为明显。犬尿氨酸3-羟化酶可能在决定脑内犬尿氨酸通量方面发挥重要作用。
