„Insights into the role of methionine synthase in the universal 13C depletion in O- and N-methyl groups of natural products” Katarzyna M. Romek, Agnieszka Krzemińska, Gerald S. Remaud, Maxime Julien, Piotr Paneth, Richard J. Robins Arch. Biochem. Biophys. 635, 60-65 (2017)