TY - JOUR T1 - S-DEMETHYLATION BY MICROSOMAL ENZYMES JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 1 LP - 6 VL - 143 IS - 1 AU - Paul Mazel AU - J. Frank Henderson AU - Julius Axelrod Y1 - 1964/01/01 UR - http://jpet.aspetjournals.org/content/143/1/1.abstract N2 - The removal of methyl groups from thioethers to yield formaldehyde and free thiols by rat liver microsomal enzymes has been demonstrated. S-Demethylation requires NADP, glucose-6-phosphate, Mg++, nicotinamide, oxygen, microsomes and a soluble NADPH-generating system. NAD does not substitute for NADP. This reaction occurs predominantly in liver, but also to a very small extent in kidney and spleen. A variety of compounds of the type R—S—CH3 are S-demethylated, including compounds in which R is a purine, hydrogen, a barbiturate, benzothiazole, an amino acid and an amidine. Rat, rabbit, and mouse liver preparations demethylated 6-methylthiopurine and methylthiopseudourea, but to different degrees suggesting more than one S-demethylating enzyme. There was no significant difference in S-demethylation between male and female rats. The Williams & Wilkins Company ER -