Methylamine dehydrogenase carries out the oxidation of methylamine. Electrons are passed from methylamine dehydrogenase to amicyanin. H2O + methylamine + 2 oxidized [amicyanin] = formaldehyde + 2 H(+) + NH4(+) + 2 reduced [amicyanin] Tetramer of two light and two heavy chains. Belongs to the aromatic amine dehydrogenase heavy chain family.