Separation of two distinct S-adenosylmethionine dependent N-methyltransferases involved in hordenine biosynthesis in Hordeum vulgare.

Hordenine is biosynthesized in young roots of barley by subsequent N-methylation of tyramine. It was shown that two distinct enzymes are responsible for these methylation reactions. They differed in their pH-optimum, their stability in dependence of the pH-value, and were partially resolved by DEAE-chromatography. More than 200-fold purification and almost complete separation were achieved by elution of the enzymes from an affinity column which was prepared by coupling S-adenosylhomocysteine to aminohexyl-Sepharose 4 B.