S-adenosyl-l-methionine: (S) -7,8,13, 14-tetrahydroberberine- [formula omitted]-n-methyltransferase, a branch point enzyme in the biosynthesis of benzophenanthridine and protopine alkaloids.

Abstract

The enzyme which transfers the CH 3-group of S-adenosylmethionine to the nitrogen atom of (S)-tetrahydroberberine and (S)-stylopine is found to occur in a number of plant cell cultures originating from species containing alkaloids; it is located at an important branch point in isoquinoline alkaloid biosynthesis.