The single berberine bridge enzyme homolog of Physcomitrella patens is a cellobiose oxidase

Abstract The berberine bridge enzyme from the California poppy Eschscholzia californica (Ec BBE) catalyzes the oxidative cyclization of (S)‐reticuline to (S)‐scoulerine, that is, the formation of the berberine bridge in the biosynthesis of benzylisoquinoline alkaloids. Interestingly, a large number of BBE‐like genes have been identified in plants that lack alkaloid biosynthesis. This finding raised the question of the primordial role of BBE in the plant kingdom, which prompted us to investigate the closest relative of Ec BBE in Physcomitrella patens