IUBMB Enzyme Nomenclature


Accepted name: 8-hydroxyfuranocoumarin 8-O-methyltransferase

Reaction: (1) S-adenosyl-L-methionine + an 8-hydroxyfurocoumarin = S-adenosyl-L-homocysteine + an 8-methoxyfurocoumarin (general reaction)
(2) S-adenosyl-L-methionine + xanthotoxol = S-adenosyl-L-homocysteine + xanthotoxin

For diagram of reaction, click here

Glossary: xanthotoxin = O-methylxanthotoxol = 8-methoxypsoralen
xanthotoxol = 8-hydroxypsoralen

Other name(s): furanocoumarin 8-methyltransferase; furanocoumarin 8-O-methyl-transferase; xanthotoxol 8-O-methyltransferase; XMT; 8-hydroxyfuranocoumarin 8-O-methyltransferase; SAM:xanthotoxol O-methyltransferase; S-adenosyl-L-methionine:8-hydroxyfuranocoumarin 8-O-methyltransferase; xanthotoxol methyltransferase; xanthotoxol O-methyltransferase; S-adenosyl-L-methionine:xanthotoxol O-methyltransferase; S-adenosyl-L-methionine-xanthotoxol O-methyltransferase

Systematic name: S-adenosyl-L-methionine:8-hydroxyfurocoumarin 8-O-methyltransferase

Comments: Converts xanthotoxol into xanthotoxin, which has therapeutic potential in the treatment of psoriasis as it has photosensitizing and antiproliferative activities [4]. Methylates the 8-hydroxy group of some hydroxy- and methylcoumarins, but has little activity on non-coumarin phenols (see also EC, 5-hydroxyfuranocoumarin 5-O-methyltransferase).

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 67339-13-3


1. Thompson, H.J., Sharma, S.K. and Brown, S.A. O-Methyltransferases of furanocoumarin biosynthesis. Arch. Biochem. Biophys. 188 (1978) 272-281. [PMID: 28084]

2. Hauffe, K.D., Hahlbrock, K. and Scheel, D. Elicitor-stimulated furanocoumarin biosynthesis in cultured parsley cells - S-adenosyl-L-methionine-bergaptol and S-adenosyl-L-methionine-xanthotoxol O-methyltransferases. Z. Naturforsch. C: Biosci. 41 (1986) 228-239.

3. Sharma, S.K., Garrett, J.M. and Brown, S.A. Separation of the S-adenosylmethionine: 5- and 8-hydroxyfuranocoumarin O-methyltransferases of Ruta graveolens L. by general ligand affinity chromatography. Z. Naturforsch. [C] 34C (1979) 387-391. [PMID: 156999]

4. Hehmann, M., Lukačin, R., Ekiert, H. and Matern, U. Furanocoumarin biosynthesis in Ammi majus L. Cloning of bergaptol O-methyltransferase. Eur. J. Biochem. 271 (2004) 932-940. [PMID: 15009205]

Note For reference 4 an accent may not be seen. č is c-hacek.

[EC created 1984, modified 2006 (EC created 2006, incorporated 2008)]

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