Dismutation of dihydrofolate by dihydrofolate reductase.
Dismutation of dihydrofolate by dihydrofolate reductase.
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二氢叶酸还原酶对二氢叶酸的歧化。
DOI：
10.1021/bi00306a009
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发表时间：
1984
期刊：
影响因子：
2.9
通讯作者：
Cocco,L
中科院分区：
文献类型：
--
作者：
Blakley,RL;Cocco,L
Raymond L. Blakley*和Lennie Coceo摘要：在二氢叶酸还原酶（DHFR）存在的情况下，7,8 -二氢叶酸（H2folate）的降解已被证明不是由于还原酶的加氧酶活性，而是由于H2folate突变为叶酸和5,6,7,8 -四氢叶酸（H4folate）。反应可以用分光光度法或高效液相色谱法对反应混合物进行分析。并对产物进行了分离和表征。在H2folate消失的情况下，反应过程中的氧气吸收率远低于stoi-chiometric，这是由于形成的H2folate的自氧化。高纯度的粪链球菌DHFR同工酶2（而非同工酶1）和干酪乳杆菌DHFR具有分化活性，而牛肝DHFR不具有分化活性。活性依赖于紧密结合的NADP+和/或NADPH。去除核苷酸会导致失配活性的丧失，而失配活性可以通过添加NADP+或NADPH来恢复。二氢叶酸还原酶（5,6,7,8 -四氢叶酸：NADP+氧化还原酶，EC 1.5）1.3;DHFR通常通过NADPH催化7,8 -二氢叶酸（h2叶酸）还原为四氢叶酸（h4叶酸）。然而，Poe（1973）报道了来自大肠杆菌b 1428的DHFR也催化H2folate在C9-N10键上的氧化裂解，并通过质子磁共振十负性鉴定了其中一个产物为7,8 -二氢蝶呤-6-甲醛。提出的反应是
Raymond L. Blakley* and Lennie Coceo abstract: Degradation of 7, 8-dihydrofolate (H2folate) in the presence of dihydrofolate reductase (DHFR) has been shown due not to an oxygenase activity of the reductase as previously reported but to dismutationof H2folate to folate and 5, 6, 7, 8-tetrahydrofolate (H4folate). The reaction can be followed spectrophotometrically or by analysis of the reaction mixture by high-performance liquid chromatography (HPLC). The products havealso been isolated and characterized. Oxygen uptake during the reaction is much less than stoi-chiometric with H2folate disappearance and is attributed to autoxidation of the H4folate formed. The dismutation activity is a property of highly purified Streptococcus faecium DHFR isoenzyme 2 (but not isoenzyme 1) and of Lactobacillus casei DHFR, but not of bovine liver DHFR. The activity is de-pendent on tightly bound NADP+ and/or NADPH. Removal of the nucleotide results in loss of dismutation activity, which is restored by adding NADP+ or NADPH. MaximumactivityDihydrofolate reductase (5, 6, 7, 8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5. 1.3; DHFR) normally catalyzes the reduction of 7, 8-dihydrofolate (H2folate) to tetrahydrofolate (H4folate) by NADPH. However, Poe (1973) reported that DHFR from Escherichia coliMB 1428 also catalyzes the oxidative cleavage of H2folate at the C9-N10 bond and ten-tatively identified one of the products by proton magnetic resonance as 7, 8-dihydropterin-6-carboxaldehyde. The reac-tion proposed was
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干酪乳杆菌二氢叶酸还原酶对氨甲蝶呤进行 TPNH 依赖性结合。
影响因子：
3.9
作者：
F. Otting;F. M. Huennekens
通讯作者：
F. M. Huennekens
来自抗甲氨蝶呤干酪乳杆菌的二氢叶酸还原酶。
影响因子：
2.9
作者：
L. Gundersen;R. Dunlap;N. Harding;J. Freisheim;F. Otting;F. M. Huennekens
通讯作者：
F. M. Huennekens
来自甲氨蝶呤耐药大肠杆菌菌株的二氢叶酸还原酶上有两个还原的三磷酸吡啶核苷酸结合位点的证据。
DOI：
10.1016/s0021-9258(19)43457-1
发表时间：
1973
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
M. N. Williams;N. Greenfield;K. Hoogsteen
通讯作者：
K. Hoogsteen
来自甲氨蝶呤抗性大肠杆菌菌株的二氢叶酸还原酶：二氢叶酸单加氧酶活性。
DOI：
10.1016/0006-291x(73)90794-8
发表时间：
1973
影响因子：
3.1
作者：
Martin Poe
通讯作者：
Martin Poe
多种形式的二氢叶酸还原酶。
DOI：
10.1016/0006-291x(68)90257-x
发表时间：
1968
影响因子：
3.1
作者：
G. P. Mell;M. Martelli;J. Kirchner;F. M. Huennekens
通讯作者：
F. M. Huennekens