AUTHOR=Hagel Jillian , Facchini Peter 

TITLE=Biochemistry and Occurrence of O-Demethylation in Plant Metabolism

JOURNAL=Frontiers in Physiology

VOLUME=1

YEAR=2010

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2010.00014

DOI=10.3389/fphys.2010.00014

ISSN=1664-042X

ABSTRACT=<p>Demethylases play a pivitol role in numerous biological processes from covalent histone modification and DNA repair to specialized metabolism in plants and microorganisms. Enzymes that catalyze <italic>O</italic>- and <italic>N</italic>-demethylation include 2-oxoglutarate (2OG)/Fe(II)-dependent dioxygenases, cytochromes P450, Rieske-domain proteins and flavin adenine dinucleotide (FAD)-dependent oxidases. Proposed mechanisms for demethylation by 2OG/Fe(II)-dependent enzymes involve hydroxylation at the <italic>O</italic>- or <italic>N</italic>-linked methyl group followed by formaldehyde elimination. Members of this enzyme family catalyze a wide variety of reactions in diverse plant metabolic pathways. Recently, we showed that 2OG/Fe(II)-dependent dioxygenases catalyze the unique <italic>O</italic>-demethylation steps of morphine biosynthesis in opium poppy, which provides a rational basis for the widespread occurrence of demethylases in benzylisoquinoline alkaloid metabolism.</p>