IUBMB Enzyme Nomenclature


Accepted name: N-methyl nucleosidase

Reaction: 7-methylxanthosine + H2O = 7-methylxanthine + D-ribose

For diagram of reaction click here

Other name(s): 7-methylxanthosine nucleosidase; N-MeNase; N-methyl nucleoside hydrolase; methylpurine nucleosidase

Systematic name: 7-methylxanthosine ribohydrolase

Comments: The enzyme preferentially hydrolyses 3- and 7-methylpurine nucleosides, such as 3-methylxanthosine, 3-methyladenosine and 7-methylguanosine. Hydrolysis of 7-methylxanthosine to form 7-methylxanthine is the second step in the caffeine-biosynthesis pathway.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1.Negishi, O., Ozawa, T. and Imagawa, H. N-Methyl nucleosidase from tea leaves. Agric. Biol. Chem. 52 (1988) 169-175.

[EC created 2007]

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