| Substrate | Acid phosphatase | Alkaline phosphatase | ||
| Wheat germ | Sweet potato | Potato | E. coli | |
| kJ∙mol−1 | ||||
| PNP | 36.1 | 30.5 | 36.8 | 28.3 |
| PNP2A2E | 35.9 | 29.5 | 34.5 | 29.3 |
| PNPBC | 34.7 | 30.1 | 47.4 | 27.2 |
| Bis-PNP | 18.0 | 22.8 | 19.2 | 15.7 |
| DG6PNa | 25.0 | 19.6 | 48.5 | 30.6 |
| DG6P2Na | 27.8 | 22.3 | 49.6 | 41.2 |