Structural reassignment of the peroxide oxidation product of 5-methyl-5,6,7,8-tetrahydrofolate.
Structural reassignment of the peroxide oxidation product of 5-methyl-5,6,7,8-tetrahydrofolate.
复制标题
5-甲基-5,6,7,8-四氢叶酸过氧化物氧化产物的结构重新分配。
DOI：
10.1016/0006-291x(81)91583-7
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发表时间：
1981
影响因子：
3.1
通讯作者：
Russell,A
中科院分区：
文献类型：
--
作者：
Whiteley,JM;Russell,A
摘要5-甲基-5，6，7，8-四氢叶酸在pH为6的条件下用过氧化氢氧化得到一个含有额外氧原子的衍生物，该氧原子可以被硼氢化物吸收两个氢原子或通过催化氢化还原。这两个化合物以前被认为是4a-羟基化的蝶类化合物[GR Gapski，JM Whiteley和FM Huennekens，BioChemical 10：2390(1971)]。在本报告中，13碳核磁共振研究表明，在氧化过程中，叶酸衍生物(相对于对氧烷的−为33ppm)的明确定义的C-4a共振消失，而在氧化产物中，在光谱的特征羰基区域出现了新的下场共振。在还原步骤之后，这种转置的共振会被对应于二次羟基取代碳原子的共振所取代。结果表明，在氧化过程中发生了蝶呤核重排。与简单的鲁马津和蝶呤系列中类似的氧化反应相比，支持这种情况。在几种可能的异构体结构中，2-氨基-8-甲基-4，9-二氧代-7-甲基-对氨基苯甲酰谷氨酸-6，7，8，9-四氢-4H-吡嗪(1，2-a)-S-三嗪及其9-羟基类似物被归属于分离产物。对先前实验结果的重新评估与这些作业是一致的。
Abstract Oxidation of 5-methyl-5, 6, 7, 8-tetrahydrofolate with hydrogen peroxide at pH 6 gives a derivative containing an extra oxygen atom, which can then be reduced with the uptake of two hydrogen atoms by borohydride or by catalytic hydrogenation. The two compounds were previously suggested to be 4a-hydroxylated pteridines [GR Gapski, JM Whiteley and FM Huennekens, Biochemistry 10: 2390 (1971)]. In this report 13 C NMR studies show the disappearance of the clearly defined C-4a resonance of the folate derivative (− 33 ppm relative to p-doxane) during oxidation, with the emergence, in the oxygenated product, of a new downfield resonance in the characteristic carbonyl region of the spectrum. After the reduction step this transposed resonance is in turn replaced by a resonance which corresponds to that of a secondary hydroxyl substituted carbon atom. The results suggest rearrangement of the pteridine nucleus has occurred during oxidation. Comparison with similar oxidation reactions in the simple lumazine and pterin series supports this occurrence. Of several possible isomeric structures 2-amino-8-methyl-4, 9-dioxo-7-methyl-p-aminobenzoylglutamate-6, 7, 8, 9-tetrahydro-4H-pyrazino (1, 2-a)-s-triazine and its 9-hydroxyl analog have been assigned to the isolated products. Reevaluation of the previous experimental findings is in accordance with these assignments.