| Nuclease | Grade | Source | Cleavage Specificity | MW (kD) | pH Optimum | Required Cofactors | Comments |
|---|---|---|---|---|---|---|---|
| RNase A | Affinity pure RPA RNA | Bovine | 3' of ss C's and U's | 13.7 | 7.0-7.5 | None | Inactivated by 0.1% SDS (1) |
| RNase I | MB* | E. coli (recombinant) | 3' of ss NTPs of RNA | 27.2 | None | Responsible for 98% of the EDTA-resistant RNase activity in E. coliextracts (2) | |
| RNase T1 | MB* RNA | A. oryzae (recombinant) | 3' of ss G's | 11.1 | 7.5 | None | Specificity for G is 106X greater than A (3) |
| RNase V1 | RNA | Cobra venom | dsRNA | 15.9 | 7.5 | Na+ (100 mM) Mg2+ (0.3 mM) | Cleaves ssRNA at 10% the rate of dsRNA (1) |
| RNase H | MB* | E. coli (recombinant) | RNA of RNA:DNA hybrids to give 5'-P oligonucleotides | 17.6 | 7.5-9.1 | Mg2+ (2–4 mM) | EDTA abolishes activity, but enzyme can still bind RNA:DNA hybrids; Not inhibited by vanadate (3) |
| DNase I | RNase-free (see also DNA-free™) | Bovine | dsDNA to yield 5'-P dinucleotides and 5'-P oligonucleotides | 29.1 | 7.0-8.0 | Mg2+ (2–5 mM) Ca2+ (0.1–1 mM) | Cleaves ssDNA 500X more slowly than dsDNA (3,4) |