大鼠体内5-甲基四氢蝶酰-L-谷氨酸及其氧化产物的代谢
The metabolism of 5-methyltetrahydropteroyl-L-glutamic acid and its oxidation products in the rat.
作者信息
Kennelly J C, Blair J A, Pheasant A E
出版信息
Biochem J. 1982 Aug 15;206(2):373-8. doi: 10.1042/bj2060373.
Folate metabolism in the rat was investigated using radiolabelled 5-methyltetrahydropteroylglutamate (5-CH3-H4PteGlu) and its oxidation products. 5-CH3-H4PteGlu is absorbed completely from the intestine, although in some preparations it is an equimolecular mixture of C-6 epimers, only one of which is naturally present in biological systems. The methyl group is incorporated into non-folate compounds, including methionine and creatine. No evidence was observed for the oxidation of the methyl group of 5-CH3-H4PteGlu to form other folate types. The tetrahydrofolate moiety of 5-CH3-H4PteGlu is metabolized in a similar manner to folic acid, forming formyl folates and tissue polyglutamates, and is catabolized by scission. The triazine oxidation product of 5-CH3-H4PteGlu is not metabolized by the rat or its gut microflora. 5-Methyl-5,6-dihydropteroylglutamate, however, is assimilated into the folate pool, but is substantially broken down by passage through the gut. The possible implication of this in scorbutic diets is discussed.
利用放射性标记的5-甲基四氢蝶酰谷氨酸（5-CH3-H4PteGlu）及其氧化产物对大鼠体内的叶酸代谢进行了研究。5-CH3-H4PteGlu可从肠道完全吸收，尽管在某些制剂中它是C-6差向异构体的等分子混合物，其中只有一种天然存在于生物系统中。甲基被掺入非叶酸化合物中，包括蛋氨酸和肌酸。未观察到5-CH3-H4PteGlu的甲基氧化形成其他叶酸类型的证据。5-CH3-H4PteGlu的四氢叶酸部分的代谢方式与叶酸相似，形成甲酰叶酸和组织多聚谷氨酸，并通过裂解进行分解代谢。5-CH3-H4PteGlu的三嗪氧化产物不会被大鼠或其肠道微生物群代谢。然而，5-甲基-5,6-二氢蝶酰谷氨酸被吸收到叶酸池中，但在通过肠道时会大量分解。文中讨论了这在坏血病饮食中的可能影响。
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