Scheme 1
The reported nicotine degradation pathways in bacteria (a) and eukaryotes (b). Nicotine degradation pathways in bacteria are represented by the pyridine pathway of A. nicotinovorans, the pyrrolidine pathway of P. putidia S16, and the VPP pathway of Ochrobactrum sp. Strain SJY1; the demethylation pathways in eukaryotes are inordinately described for A. oryzae 112822, M. gypseum ATCC11395, P. filamentosa JTS-208, C. echinulata IFO-4444, Nicotiana plumbaginifolia and human. NDHSML, nicotine dehydrogenase; VppASL, nicotine hydroxylase; 6HLNO and VppB, 6-HN oxidases; KDHSML, ketone dehydrogenase; DHPONH, 2, 6-dihydroxypseudooxynicotine hydrolase; DHPH, 2, 6-dihydroxypyridine 3-hydroxylase; AO, amine oxidase; MABO, γ-N-methylaminobutyrate oxidase; NicA1 and NicA2, nicotine oxidoreductases; Pnao, pseudooxynicotine amidase; Sapd, 3-succinoyl-semialdehyde-pyridine dehydrogenase; SpmABC, 3-succinoyl-pyridine monooxygenase; HspB and VppD, HSP 3-monooxygenases; Hpo and VppE, 2, 5-DHP dioxygenases; Nfo and VppF, N-formylmaleamic acid deformylases; VppG and Ami, maleamate amidases; Iso and VppH, maleate isomerases