What is "methylnitronitrosoguanidine"

n. A biochemical substance used experimentally as a carcinogen and mutagen. It acts by adding alkyl groups to the O⁶ of guanine and O⁴ of thymine.

Methylnitronitrosoguanidine (MNNG or MNG) is a biochemical tool used experimentally as a carcinogen and mutagen. It acts by adding alkyl groups to the O of guanine and O of thymine, which can lead to transition mutations between GC and AT. These changes do not cause a heavy distortion in the double helix of DNA and thus are hard to detect by the DNA mismatch repair system.

In organic chemistry, MNNG is used as a source of diazomethane when reacted with aqueous potassium hydroxide.

MNNG is a probable human carcinogen listed as an IARC Group 2A carcinogen.