Table 2.
Enzyme-prodrug systems under investigation for genetic prodrug activation therapy applications
| Enzyme | Prodrug | Cytotoxic product |
| Herpes simplex virus thymidine kinase | Ganciclovir | Ganciclovir triphosphate |
| Cytosine deaminase | 5-Fluorocytosine | 5-Fluorouracil |
| Varicella zoster virus thymidine kinase | 6-Methoxypurine arabinose | Adenine arabinonucleoside triphosphate |
| Nitroreductase | CB1954 | 5-Aziridinyl-4-hydroxylamino-2-nitrobenzamide |
| Cytochrome p450 | Cyclophosphamide | Acrolein and phosphoramide mustard |
| Thymidine phosphorylase | 5' -Deoxy-5-fluorouridine | 5-Fluorouracil |
| Purine nucleoside phosphorylase | 6-Methylpurine-deoxyriboside | 6-Methylpurine |
| Alkaline phosphatase | Etoposide phosphate | Etoposide |
| Carboxypeptidase A | Methotrexate-alanine | Methotrexate |
| Carboxypeptidase G2 | Benzoic acid mustard-glucuronide | Benzoic acid mustard |
| Linamarase | Linamarin | Cyanide |
| Xanthine oxidase | Xanthine | Oxygen radicals |
| β -Lactamase | Cephalosporin-mustard-carbamate | Nitrogen mustard |