四氢叶酸辅因子在成年彭亨布鲁线虫和犬恶丝虫从头合成嘌呤核糖核苷酸中的作用。

Involvement of tetrahydrofolate cofactors in de novo purine ribonucleotide synthesis by adult Brugia pahangi and Dirofilaria immitis.

作者信息

Jaffe J J, Chrin L R

出版信息

Mol Biochem Parasitol. 1981 Apr;2(5-6):259-70. doi: 10.1016/0166-6851(81)90079-7.

Abstract

Adult Brugia pahangi in vitro, unlike mouse leukemia L1210 cells, converted 5-methyltetrahydrofolate (CH3FH4) directly to 5,10-methylenetetrahydrofolate and thence to other FH4 cofactors. The excreted CO2 that was derived from CH3FH4 was due to the presence within the filariae of 10-formyltetrahydrofolate dehydrogenase (EC 1.5.1.6) which catalyzes the deformylation of 10-formyl-tetrahydrofolate. Adult B. pahangi and Dirofilaria immitis, incubated in a purine-free medium containing [5-14C]CH3FH4 as the only form of folate, synthesized purine ribonucleotides radiolabeled at positions 2 and 8 of the purine ring. Presumably, 10-formyl[14C]FH4 donated Carbon 2 during the synthesis de novo of the purine ring and 5,10-methenyl[14C]FH4 donated Carbon 8.

摘要

与小鼠白血病L1210细胞不同，体外培养的成年彭亨布鲁线虫可将5-甲基四氢叶酸（CH3FH4）直接转化为5,10-亚甲基四氢叶酸，进而转化为其他四氢叶酸辅酶。源自CH3FH4的呼出二氧化碳是由于丝虫体内存在10-甲酰四氢叶酸脱氢酶（EC 1.5.1.6），该酶催化10-甲酰四氢叶酸的脱甲酰基反应。成年彭亨布鲁线虫和犬恶丝虫在不含嘌呤的培养基中培养，该培养基含有[5-14C]CH3FH4作为唯一的叶酸形式，合成了嘌呤环2位和8位带有放射性标记的嘌呤核糖核苷酸。据推测，在嘌呤环的从头合成过程中，10-甲酰[14C]FH4提供了第2位碳原子，5,10-亚甲基[14C]FH4提供了第8位碳原子。