N-Methyltransferase involved in gramine biosynthesis in barley: Cloning and characterization

An O-methyltransferase (EC 2.1.1.6, GenBank accession U54767) was absent in barley genotypes lacking gramine. The recombinant purified protein methylated two substrates in the pathway to gramine: 3-aminomethylindole (AMI) and N-methyl-3-aminomethylindole (MAMI) but not the earlier suggested substrate, caffeic acid. We propose that U54767 is an N-methyltransferase acting in gramine biosynthesis.