7-methylxanthosine synthase

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In enzymology, a 7-methylxanthosine synthase (EC 2.1.1.158) is an enzyme that catalyzes the chemical reaction

S-adenosyl-L-methionine + xanthosine $\rightleftharpoons$ S-adenosyl-L-homocysteine + 7-methylxanthosine

Thus, the two substrates of this enzyme are S-adenosyl methionine and xanthosine, whereas its two products are S-adenosylhomocysteine and 7-methylxanthosine.

This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. The systematic name of this enzyme class is S-adenosyl-L-methionine:xanthosine N7-methyltransferase. Other names in common use include xanthosine methyltransferase, XMT, xanthosine:S-adenosyl-L-methionine methyltransferase, CtCS1, CmXRS1, CaXMT1, and S-adenosyl-L-methionine:xanthosine 7-N-methyltransferase.

[edit] References

IUBMB entry for 2.1.1.158
BRENDA references for 2.1.1.158 (Recommended.)
PubMed references for 2.1.1.158
PubMed Central references for 2.1.1.158
Google Scholar references for 2.1.1.158
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Uefuji H, Ogita S, Yamaguchi Y, Koizumi N, Sano H (2003). "Molecular cloning and functional characterization of three distinct N-methyltransferases involved in the caffeine biosynthetic pathway in coffee plants". Plant. Physiol. 132: 372–80. doi:10.1104/pp.102.019679. PMID 12746542.
Yoneyama N, Morimoto H, Ye CX, Ashihara H, Mizuno K, Kato M (2006). "Substrate specificity of N-methyltransferase involved in purine alkaloids synthesis is dependent upon one amino acid residue of the enzyme". Mol. Genet. Genomics. 275: 125–35. doi:10.1007/s00438-005-0070-z. PMID 16333668.