DNA polymerase delta (DNA polymerase III) participates in chromosomal DNA replication. It is required during synthesis of the leading and lagging DNA strands at the replication fork and binds at/or near replication origins and moves along DNA with the replication fork. It has 3'-5' proofreading exonuclease activity that correct errors arising during DNA replication. It is also involved in DNA synthesis during DNA repair. a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) DNA polymerase delta is a heterotrimer of POL3, POL32 and HYS2. Present with 626 molecules/cell in log phase SD medium. Belongs to the DNA polymerase delta/II small subunit family.