Fig. 3

Pyrrolidine pathways of nicotine degradation have been identified in various Pseudomonas species: Pseudomonas sp. HZN6, Pseudomonas sp. HF-1, Pseudomonas sp. Nic22, and Pseudomonas sp. CS3. Key enzymes involved include nicotine oxidoreductase (NicA), pseudooxynicotine amine oxidase (PNAO), 3-succinoylsemialdehyde pyridine dehydrogenase (SAPD), and 6-hydroxy-3-succinoyl pyridine hydroxylases (HspA and HspB)