Catalyzes the deamination of pseudooxynicotine to 3-succinoylsemialdehyde-pyridine in the nicotine degradation pathway. H2O + O2 + pseudooxynicotine = 4-oxo-4-(pyridin-3-yl)butanal + H2O2 + methylamine Ag(+), Co(2+), Cu(2+) and Hg(2+). kcat is 151 sec(-1) with pseudooxynicotine as substrate. Optimum pH is 8.0. Alkaloid degradation; nicotine degradation. Belongs to the flavin monoamine oxidase family.