二氢叶酸

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| verifiedrevid = 443685970
| ImageFile = Dihydrofolic acid.svg
| ImageSize = 260px
| ImageAlt = Skeletal formula of dihydrofolic acid
| ImageFile1 = Dihydrofolic-acid-3D-spacefill.png
| ImageSize1 = 250
| ImageAlt1 = Space-filling model of the dihydrofolic acid molecule
| IUPACName = N-(4-{[(2-amino-4-oxo-1,4,7,8-tetrahydropteridin-6-yl)methyl]amino}benzoyl)-L-glutamic acid
| OtherNames = H2folate, DH
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二氢叶酸（）是一个叶酸衍生物，被二氢叶酸还原酶作用后会生成四氢叶酸。因为动植物需要四氢叶酸制造嘌呤与嘧啶，故许多药物的靶点都指向二氢叶酸还原酶以阻止核酸的合成。二氢叶酸也可被叫做二氢叶酸盐，更常用的名称是维生素B9。