Many enzymes are involved in DNA replication, including DNA helicase, DNA polymerase, topoisomerase, DNA gyrase, DNA ligase, primase and telomerase. Replication is a complex process with many steps, all of which require enzymes specifically made for each particular step in the reaction.
Like nearly all cellular functions, DNA replication involves a series of chemical reactions. Enzymes are proteins manufactured by the cell for the specific purpose of allowing a particular chemical reaction to take place rapidly and efficiently. For example, the enzyme maltase is shaped precisely to accept a maltose molecule and break it down into two molecules of glucose. The enzyme is not consumed in the process and can be used repeatedly.