Some Important Enzymes and Their Role in Replication

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.