IUBMB Enzyme Nomenclature


Accepted name: sterigmatocystin 8-O-methyltransferase

Reaction: (1) S-adenosyl-L-methionine + sterigmatocystin = S-adenosyl-L-homocysteine + 8-O-methylsterigmatocystin
(2) S-adenosyl-L-methionine + dihydrosterigmatocystin = S-adenosyl-L-homocysteine + 8-O-methyldihydrosterigmatocystin

For diagram of reaction click here.

Glossary: sterigmatocystin = 3a,12c-dihydro-8-hydroxy-6-methoxyfuro[3',2':4,5]furo[2,3-c]xanthen-7-one
dihydrosterigmatocystin = 1,2,3a,12c-tetrahydro-8-hydroxy-6-methoxyfuro[3',2':4,5]furo[2,3-c]xanthen-7-one
8-O-methylsterigmatocystin = 6,8-dimethoxy-3a,12c-dihydrofuro[3',2':4,5]furo[2,3-c]xanthen-7-one
8-O-methyldihydrosterigmatocystin = 6,8-dimethoxy-1,2,3a,12c-tetrahydrofuro[3',2':4,5]furo[2,3-c]xanthen-7-one

Other name(s): sterigmatocystin methyltransferase; O-methyltransferase II; sterigmatocystin 7-O-methyltransferase (incorrect); S-adenosyl-L-methionine:sterigmatocystin 7-O-methyltransferase (incorrect); OmtA

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

Comments: Dihydrosterigmatocystin can also act as acceptor. Involved in the biosynthesis of aflatoxins in fungi.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 116958-29-3


1. Bhatnagar, D., McCormick, S.P., Lee, L.S. and Hill, R.A. Identification of O-methylsterigmatocystin as an aflatoxin B1 and G1 precursor in Aspergillus parasiticus. Appl. Environ. Microbiol. 53 (1987) 1028-1033. [PMID: 3111363]

2. Yabe, K., Ando, Y., Hashimoto, J. and Hamasaki, T. 2 distinct O-methyltransferases in aflatoxin biosynthesis. Appl. Environ. Microbiol. 55 (1989) 2172-2177. [PMID: 2802602]

3. Yu, J., Cary, J.W., Bhatnagar, D., Cleveland, T.E., Keller, N.P. and Chu, F.S. Cloning and characterization of a cDNA from Aspergillus parasiticus encoding an O-methyltransferase involved in aflatoxin biosynthesis. Appl. Environ. Microbiol. 59 (1993) 3564-3571. [PMID: 8285664]

4. Lee, L.W., Chiou, C.H. and Linz, J.E. Function of native OmtA in vivo and expression and distribution of this protein in colonies of Aspergillus parasiticus. Appl. Environ. Microbiol. 68 (2002) 5718-5727. [PMID: 12406770]

[EC created 1992, modified 2005, modified 2013]

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