DNA Polymerase

 DNA Polymerase is an enzyme which promotes or catalyzes the joining of deoxyribonucleotide units (Phosphodiester bond formation) to form a DNA strand. It is essentially involved in DNA replication and DNA repair. During DNA replication, DNA polymerase requires the presence of a template DNA strand which it copies and synthesizes a new DNA strand. The newly synthesized DNA strand is complementary to the template strand. The catalytic activity of joining the deoxyribonucleotide requires four precursors which are the deoxynucleoside 5' triphosphates dATP, dGTP, dCTP and TTP. Magnesium ion is also required for the catalytic activity.