Involved in the degradation of L-nicotine (PubMed:25002425). Catalyzes the oxidation of (S)-6-hydroxynicotine (6-hydroxy-L-nicotine) to 6-hydroxypseudooxynicotine (PubMed:25002425). Oxidation of the pyrrolidine ring of (S)-6-hydroxynicotine leads to the formation of the optically inactive 6-hydroxy-N-methylmyosmine, which hydrolyzes spontaneously to 6-hydroxypseudooxynicotine (PubMed:25002425). Acts with absolute stereospecificity on the L-form of 6-hydroxynicotine (PubMed:25002425). Also involved in the degradation of nornicotine, and catalyzes the oxidation of 6-hydroxynornicotine to 6-hydroxymyosmine, which hydrolyzes to 6-hydroxypseudooxynornicotine (PubMed:27568381). In vitro, converts (S)-nicotine into N-methylmyosmine, which spontaneously hydrolyzes spontaneously into pseudooxynicotine, but catalytic efficiency is about 1900-fold higher with (S)-6-hydroxynicotine (PubMed:25002425). (S)-6-hydroxynicotine + H2O + O2 = 6-hydroxypseudooxynicotine + H2O2 (S)-6-hydroxynicotine + O2 = 6-hydroxy-N-methylmyosmine + H2O2 Binds 1 FAD per subunit. Partially inhibited by Co(2+) or Zn(2+) and significantly inhibited by Ag(+), Cu(2+) and Hg(2+). kcat is 7.3 sec(-1) with (S)-6-hydroxynicotine as substrate. kcat is 0.396 sec(-1) with nicotine as substrate (PubMed:25002425). kcat is 5.9 sec(-1) with 6-hydroxynornicotine as substrate (PubMed:27568381). Optimum pH is 7.0. Stable between pH 6.0 and 9.8. Optimum temperature is 40 degrees Celsius. Stable at temperatures lower than 50 degrees Celsius. Alkaloid degradation; nicotine degradation; 6-hydroxypseudooxynicotine from nicotine (S-isomer route): step 2/2. Homodimer. Disruption of the gene abolishes the ability of the mutant to degrade (S)-6-hydroxynicotine. Belongs to the flavin monoamine oxidase family.