Fig. 6
Biocatalytic demethylation of various methyl phenyl ethers employing cobalamin-dependent MTase I from D. hafniense. Reaction conditions: substrate (10 mM), methyl acceptor 2a-c (50 mM, if not indicated otherwise), MTase I (freeze-dried CFE, 40 mg mL−1), CP (400 µL mL−1 reconstituted solution) in MOPS/KOH buffer (50 mM, pH 6.5, 150 mM KCl) at 30 °C, 800 rpm for 24 h. Conversions determined by HPLC-UV from areas for substrate and demethylated product, if not indicated otherwise, using calibration curves. Since the reaction has no by-products, thus the chemoselectivity was >99%, the conversion corresponds to the amount of product formed. Deviation values (s.e.m., n = 3) lie between 0.1 and 3.3 % for the substrates tested. [i] Reaction conditions as described but using methyl acceptor 2a-c at 10 mM concentration. [ii] Conversion determined by HPLC-UV from areas for the methylated acceptor using calibration curves and related to the limiting substrate concentration. Deviation values (s.e.m., n = 3) lie between 0.2 and 0.4% for the substrates tested
