What is the first restriction endonuclease?
1968: First Restriction Enzymes Described. … Restriction enzymes recognize and cut specific short sequences of DNA. They're found in bacteria, which use the enzymes to digest invading DNA. The bacteria add methyl groups to their own DNA to protect them from digestion.
Which polymerase is active in DNA repairing?
DNA polymerase alpha is required for semi-conservative replication of DNA but not for repair of DNA. A more recently discovered enzyme, DNA polymerase zeta, appears to be involved in the bypass of damage, without excision, and occurs during DNA replication of a damaged template.