CHAPTER 3
DNA Polymerases (EC 2.7.7.7)
Martin J. Maunders
- Introduction
DNA polymerases catalyze the synthesis of DNA molecules from
monomeric deoxynucleotide triphosphate units. This definition encom-
passes those enzymes classed as DNA-dependent DNA polymerases
(EC 2.7.7.7, which require both a DNA template strand and a DNA
primer to which the monomeric units can be added), reverse tran-
scriptases (EC 2.7.7.49, RNA-dependent DNA polymerases that uti-
lize an RNA template), and terminal deoxynucleotidyl transferases
(EC 2.7.7.31, which require no template). This chapter will consider
only DNA-dependent DNA polymerases (EC 2.7.7.7, DNA
nucleotidyltransferases, DNA-directed).
DNA-dependent DNA polymerases are a class of enzyme that is
essential for the replication and maintenance of all organisms. All
perform essentially the same reaction, the addition of monomeric units
to synthesize a complementary copy of an existing DNA template.
This activity can be used in molecular biology for a wide range of
techniques. These include the labeling of DNA molecules, terminally
or throughout the sequence, for use as probes or for sequence determi-
nation, the modification of DNA termini for facilitating subsequent
manipulations, the production of double-stranded cDNA, the exten-
sion of mismatched sequences for site-directed mutagenesis, the exten-
sion of synthetic DNA sequences for gene synthesis, and the specific
amplification of limiting quantities of DNA for analysis.
From: Methods in Molecular Biology, Vol. 16: Enzymes of Molecular Biology
Edited by: M. M. Burrell Copyright ©1993 Humana Press Inc., Totowa, NJ
17