Table 2. Substrate specificity of recombinant flavin-dependent monooxygenases of Z. variegatus.
| Substrate | Specific activity (nkat/mg) | |||
| GgPNO | ZvPNO | ZvFMOa | ZvFMOc | |
| Pyrrolizidine alkaloids | ||||
| Senecionine type | ||||
| Senecionine | 55.0 | 32.0 | 0.1 | 0.1 |
| Seneciphylline | 53.2 | 29.4 | 0.6 | 0.1 |
| Senecivernine | - | 24.0 | 1.3 | 0.6 |
| Retrorsine | - | 18.6 | 1.5 | 0.5 |
| Senkirkine | n.d. | n.d. | n.d. | n.d. |
| Monocrotaline type | ||||
| Monocrotaline | 90.2 | 23.4 | 1.5 | 0.9 |
| Axillarine | 62.2 | 18.6 | n.d. | n.d. |
| Axillaridine | - | 11.8 | n.d. | n.d. |
| Lycopsamine type | ||||
| Heliotrine | 44.2 | 19.5 | n.d. | n.d. |
| Rinderine | 38.8 | 11.5 | 1.3 | 0.4 |
| Indicine | - | 4.8 | n.d. | n.d. |
| Triangularine type | ||||
| Sarracine | - | 16.0 | 0.4 | 0.3 |
| Phalaenopsine type | ||||
| Phalaenopsine | 17.1 | 9.6 | n.d. | n.d. |
| Necine bases | ||||
| Retronecine | n.d. | 10.2 | n.d. | 0.1 |
| Heliotridine | - | n.d. | n.d. | n.d. |
| Supinidine | n.d. | n.d. | n.d. | n.d. |
| Other alkaloids | ||||
| Ephedrine | - | n.d. | n.d. | n.d. |
| Nicotine | n.d. | 2.3 | 0.3 | 0.4 |
| Atropine | 18.9 | 29.1 | 0.3 | n.d. |
| Other substrates | ||||
| Dimethylaniline | n.d. | n.d. | n.d. | n.d. |
| Cysteamine | n.d. | 7.0 | 0.5 | 0.1 |
| L-Cysteine | n.d. | n.d. | n.d. | n.d. |
| Hydroxylamine | - | n.d. | n.d. | n.d. |
| Glutathione | 37.0 | n.d. | n.d. | n.d. |
n.d., not detectable; -, not tested.
PA N-oxygenase (ZvPNO) and two related FMOs of Z. variegatus (ZvFMOa and ZvFMOc) have been assayed in comparison to the previously characterized recombinant PA N-oxygenase (GgPNO) of G. geneura (Arctiidae, Lepidoptera) [17].