Polymerases

Lecture Date: 9/19/25

General Polymerase Info and Definition

• Enzymes that synthesize in a template dependent manner

• Can make DNA or RNA complimentary to the template strand

• Template can be DNA or RNA

• Product can be DNA or RNA

• Very Accurate

• Many polymerases can edit (detect and fix mistakes)

• Most organisms have several different types of polymerases

• Can be described as…

  • “______ (template) dependent _____ (product) polymerase”

  • Ex. DNA dependent DNA polymerase

DNA Replication

• Parent strands become separated and the daughter strand is produced based on the complimentary bases to the parent strand

Arthur Kornberg (1959)

Took a biochemists approach:

• Ground up E. coli to liberate the proteins

• Separated the different proteins

• Looked for polymerase activity in different proteins by adding nucleotides and a template to observe if there was new strand synthesis

• Discovered DNA Polymerase I

DNA Polymerase I:

• Works only in the 5’ to 3’ direction (adding onto the 3’ end)

• Cannot start replication from single stranded DNA (needed a little portion of double stranded DNA)

• Requires ATP, CTP, GTP, TTP

• Needs a primer

• The enzyme falls off after only a few bases