Purification and characterization of O-methyltransferase I involved in conversion of demethylsterigmatocystin to sterigmatocystin and of dihydrodemethylsterigmatocystin to dihydrosterigmatocystin during aflatoxin biosynthesis - Hamasaki, Takashi.; Koyama, Takumi.; Matsushima, Ken-ichiro.; Yabe, Kimiko.