5-Hydroxymethylcytosine is a DNA pyrimidine nitrogen base. It is formed from the DNA base cytosine by adding a methyl group and then a hydroxy group. It is important in epigenetics, because the hydroxymethyl group on the cytosine can possibly switch a gene on and off. It was first seen in bacteriophages in 1952. However, in 2009 it was found to be abundant in human and mouse brains, as well as in embryonic stem cells. In mammals, it can be generated by oxidation of 5-methylcytosine, a reaction mediated by the Tet family of enzymes. Its molecular formula is C5H7N3O2.

CAS：1123-95-1
中文别名：4-氨基-5-(羟甲基)嘧啶-2-醇;2-羟基-4-氨基-5-甲基吡啶;4-氨基-2-羟基-5-羟甲基嘧啶;2-羟基-6=氨基-5-羟甲基嘧啶;5-羟甲基胞嘧啶;5-羟甲基胞间二氮苯;
英文别名：6-amino-5-(hydroxymethyl)-1H-pyrimidin-2-one;4-AMINO-2-HYDROXY-5-(HYDROXYMETHYL)PYRIMIDINE;5-Hydroxymethylcytosine;2(1H)-Pyrimidinone, 4-amino-5-(hydroxymethyl)-;
分子式：C5H7N3O2
分子量：141.128
精确质量：141.054
Psa：92.26
Logp：-0.1621

MDL号：MFCD00047369

密度：1.65g/cm3
折射率：1.696

海关编码：2933990090
危险品标志：Xi