In enzymology, a demethylsterigmatocystin 6-O-methyltransferase is an enzyme that catalyzes the chemical reaction S-adenosyl-L-methionine + 6-demethylsterigmatocystin ⇌ {\displaystyle \rightleftharpoons } S-adenosyl-L-homocysteine + sterigmatocystinThus, the two substrates of this enzyme are S-adenosyl methionine and 6-demethylsterigmatocystin, whereas its two products are S-adenosylhomocysteine and sterigmatocystin. Wikipedia