Under investigation are the enzymes concerned with the detoxication of amines. Two Isoenzymes have prepared in homegeneous form from rabbit liver, amine N-methyl transferases A and B, each of which catalyzes, with very similar specificity, the transfer of methyl groups from S-adenosyl-L-methionine to a large number of amines. The amine acceptors include primary, secondary and tertiary amines of very different carbon skeleton that include aliphatic, aromatic and heterocyclic amines. It will be noted that the product of methylation of azaheterocycles is frequently a quaternary ion. A second type of conjugation reaction with amines is that in which amines serve as receptors for a sulfuryl group from 3'- phosphoadenosine 5'-phosphosulfate. The result is the formation of a sulfamate, a reaction that occurs with a variety of both primary and secondary amines and is catalyzed by amine N- sulfotransferase isolated from guinea pig liver. One substrate is cyclohexylamine which undergoes sulfuryl transfer to form sulfamate, the sugar substitute cyclamate.
