Which enzyme is considered the main polymerizing enzyme for both leading and lagging strands?

The main polymerizing enzyme for both the leading and lagging strands during DNA replication is DNA polymerase delta (Pol δ). This enzyme plays a crucial role in synthesizing the new strands of DNA by adding nucleotides complementary to the template strand.

DNA polymerase δ is particularly important for replication because it possesses high processivity, meaning it can add a significant number of nucleotides before dissociating from the template strand. This characteristic makes it well-suited for the continuous synthesis occurring on the leading strand and the discontinuous synthesis that happens on the lagging strand, where it synthesizes Okazaki fragments.

In contrast, other polymerases, such as DNA polymerase alpha (Pol α), are primarily involved in initiating DNA synthesis and do not perform the main polymerization during replication. DNA polymerase epsilon (Pol ε) is mainly associated with leading strand synthesis in eukaryotic cells, but it does not directly influence lagging strand synthesis to the same extent as Pol δ. Polymerase beta (Pol β) is generally involved in DNA repair rather than DNA replication. Thus, Pol δ is recognized as the key enzyme responsible for polymerization in both strands during DNA replication.