Table 1 Classification of human P450s based on major substrate class
| Steroids | Xenobiotics | Fatty acids | Eicosanoids | Vitamin | Unknown |
|---|---|---|---|---|---|
| 1B1* | 1A1* | 2J2 | 2U1 | 2R1* | 2A7 |
| 7A1* | 1A2* | 2S1 | 4F2 | 24A1** | 4X1 |
| 7B1 | 2A6* | 2U1 | 4F3 | 26B1 | 20A1 |
| 8B1 | 2A13* | 4A11 | 4F8 | 26C1 | |
| 11A1* | 2B6* | 4A22 | 5A1 | 27B1 | |
| 11B1* | 2C8* | 4B1** | 8A1* | 27C1 | |
| 11B2* | 2C9* | 4F11 | |||
| 17A1* | 2C18 | 4F12 | |||
| 19A1* | 2C19* | 4F22 | |||
| 21A2* | 2D6* | 4V2 | |||
| 27A1 | 2E1* | 4Z1 | |||
| 39A1 | 2F1 | ||||
| 46A1* | 2W1 | ||||
| 51A1* | 3A4* | ||||
| 3A5* | |||||
| 3A7* | |||||
| 3A43 |
This classification is somewhat arbitrary in some cases, e.g., P450s 1B1 and 27A1 could be grouped in either of two different categories.
*Crystal structure available. **Crystal structure of animal orthologue available.