| Name of the Enzyme |
Role in DNA Replication |
| 1. Endonuclease (incision enzyme) |
Causes nick (break) in the DNA strand at the point of origin. |
| 2. DNA helicase (also called rep protein or DNA unwinding protein) |
Brings about unwinding of the two strands of DNA molecule (This enzyme needs ATP energy for unwinding). |
| 3. DNA gyrase (topoiosomerase) |
Removes the supercoils in the DNA double helix which are developed ahead of the replication fork during the unwinding. |
| 4. SSBP (single Strand DNA Binding Protein)also called SSB or Helix destabilizing protein). |
Prevents the separated strands of the DNA molecules from coiling around each other again. |
| 5. DNA primase |
Catalyses synthesis of RNA primer |
| 6. DNA polymerase (DNA replicases). |
These enzymes bring about synthesis of new strand of DNA on each old template strand. |
| 7. DNA ligase (Poynucleotide ligases). |
These enzymes are responsible for joining the Okazaki fragments of the new lagging strand during replication. |