2-methoxy-5-methyl-6-all-trans-hexaprenyl-1,4-benzoquinone + NADH + O2 => 3-demethylubiquinone-6 + NAD(+) + H2O
2-methoxy-5-methyl-6-all-trans-hexaprenyl-1,4-benzoquinone + nadh + o2 => 3-demethylubiquinone-6 + nad(+) + h2o