methyl methanesulfonate methyl methanesulfonate methyl methanesulfonate (mms), also known as methyl mesylate, is an alkylating agent and a carcinogen. it is also a suspected reproductive toxicant, and may also be a skin/sense organ toxicant. it is used in cancer treatment. methyl methanesulfonate skeletal formula ball-and-stick model names preferred iupac name methyl methanesulfonate other names methanesulfonic acid methyl estermethyl mesylatemms identifiers cas number 66-27-3 y 3d model (jsmol) interactive image chebi chebi:25255 n chemspider 4013 n echa infocard 100.000.568 ec number 200-625-0 kegg c19181 y mesh d008741 pubchem cid 4156 unii at5c31j09g y comptox dashboard (epa) dtxsid7020845 inchi inchi=1s/c2h6o3s/c1-5-6(2,3)4/h1-2h3 nkey: mbabokrgfjtbae-uhfffaoysa-n ninchi=1/c2h6o3s/c1-5-6(2,3)4/h1-2h3key: mbabokrgfjtbae-uhfffaoyak smiles cos(=o)(=o)c properties chemical formula c2h6o3s molar mass 110.13 g/mol density 1.3 g/ml at 25 °c boiling point 202 to 203 °c (396 to 397 °f; 475 to 476 k) related compounds related compounds ethyl methanesulfonate, dimethyl sulfone, dimethyl sulfate except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). n verify (what is yn ?) infobox references chemical reactions with dna mms methylates dna predominantly on n7-deoxyguanosine and n3-deoxyadenosine, and to a much lesser extent also methylates at other oxygen and nitrogen atoms in dna bases, and also methylates one of the non-carbon bound oxygen atoms of the phosphodiester linkage. originally, this action was believed to directly cause double-stranded dna breaks, because homologous recombination-deficient cells are particularly vulnerable to the effects of mms. however, it is now believed that mms stalls replication forks, and cells that are homologous recombination-deficient have difficulty repairing the damaged replication forks.