GTP环水解酶I
四氢生物蝶呤
苯丙氨酸
苯丙氨酸羟化酶
高苯丙氨酸血症
GTP'
鸟苷
化学
生物化学
鸟苷三磷酸
辅因子
酶
氨基酸
作者
Toshiaki Harada,Hiroyuki Kagamiyama,Kazuyuki Hatakeyama
出处
期刊:Science
[American Association for the Advancement of Science (AAAS)]
日期:1993-06-04
卷期号:260 (5113): 1507-1510
被引量:151
标识
DOI:10.1126/science.8502995
摘要
Guanosine triphosphate (GTP) cyclohydrolase I, the rate-limiting enzyme in the biosynthesis of tetrahydrobiopterin (BH4), is subject to feedback inhibition by BH4, a cofactor for phenylalanine hydroxylase. Inhibition was found to depend specifically on BH4 and the presence of another protein (p35). The inhibition occurred through BH4-dependent complex formation between p35 protein and GTP cyclohydrolase I. Furthermore, the inhibition was specifically reversed by phenylalanine, and, in conjunction with p35, phenylalanine reduced the cooperativity of GTP cyclohydrolase I. These findings also provide a molecular basis for high plasma BH4 concentrations observed in patients with hyperphenylalaninemia caused by phenylalanine hydroxylase deficiency.
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