1.14.14.117 aflatoxin B synthase aflatoxins B2 and G2 biosynthesis 2.1.1.109 demethylsterigmatocystin 6-O-methyltransferase aflatoxins B2 and G2 biosynthesis 2.1.1.110 sterigmatocystin 8-O-methyltransferase aflatoxins B2 and G2 biosynthesis