MTRR（5-methyltetrahydrofolate-homocysteine methyltransferase reductase），癌症关联基因，基因ID：4552，该基因编码一个成员的铁氧还蛋白NADP（+）还原酶（FNR）家族的电子转移酶。该蛋白通过将蛋氨酸合酶再生到功能状态在蛋氨酸合成中发挥作用。由于蛋氨酸合成需要叶酸供体的甲基转移，编码酶的活性对叶酸代谢和细胞甲基化很重要该基因突变可引起同型膀胱尿巨幼细胞性贫血，cbl E型该基因的选择性剪接导致多个转录变体。[由RefSeq提供，2015年12月]This gene encodes a member of the ferredoxin-NADP(+) reductase (FNR) family of electron transferases. This protein functions in the synthesis of methionine by regenerating methionine synthase to a functional state. Because methionine synthesis requires methyl-group transfer by a folate donor， activity of the encoded enzyme is important for folate metabolism and cellular methylation. Mutations in this gene can cause homocystinuria-megaloblastic anemia， cbl E type. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq， Dec 2015]。