xanthosine + S-adenosyl-L-methionine = 7-methylxanthosine + S-adenosyl-L-homocysteine
xanthosine + s-adenosyl-l-methionine = 7-methylxanthosine + s-adenosyl-l-homocysteine
"xanthosine methyltransferase"
"xanthosine methyltransferase"