Table 5
Distribution of Ni-dependent enzymes in archaea
| Phylum | Total organisms | Ni-utilizing organisms | Ni-utilizing organisms containing different Ni-dependent proteins | ||||
| Urease | Ni-Fe hydrogenase | Ni-CODH | CODH/ACS | MCR* | |||
| Nanoarchaeota | 1 | - | - | - | - | - | - |
| Crenarchaeota/Thermoproteales | 6 | 4 | - | 4 | - | - | - |
| Crenarchaeota/Desulfurococcales | 4 | 3 | - | 3 | - | - | - |
| Crenarchaeota/Sulfolobales | 4 | 3 | 2 | 2 | - | - | - |
| Euryarchaeota/Thermoplasmales | 4 | 3 | - | 3 | - | - | - |
| Euryarchaeota/Archaeoglobales | 1 | 1 | - | 1 | 1 | 1 | - |
| Euryarchaeota/Halobacteriales | 5 | 3 | 3 | - | - | - | - |
| Euryarchaeota/Methanosarcinales | 5 | 5 | - | 3 | 4 | 5 | 5 |
| Euryarchaeota/Thermococcales | 4 | 4 | - | 4 | - | - | - |
| Euryarchaeota/Methanococcales | 5 | 5 | - | 5 | 1 | 5 | 5 |
| Euryarchaeota/Methanopyrales | 1 | 1 | - | 1 | 1 | 1 | 1 |
| Euryarchaeota/Methanobacteriales | 3 | 3 | - | 3 | - | 1 | 3 |
| Euryarchaeota/Methanomicrobiales | 4 | 4 | - | 4 | 2 | 2 | 4 |
| Total | 47 | 39 | 5 | 33 | 9 | 15 | 18 |
*: MCR, Methyl-coenzyme M reductase.