| Denaturant | Result with linear DNA | Result with circular DNA |
| Boiling | Strand separation | Nothing ? no strand separation1 |
| Alkali | Strand separation | Denaturation to Form IV2 |
| Weak organic solvents3 | Strand separation | Nothing ? no strand separation |
| Strong organic solvents4 | Strand separation | Denaturation to Form IV2 |