Methods in Molecular Biology • 16 Enzymes of Molecular Biology

CHAPTER 4

Taq Polymerase (EC 2.7.7.7)

With Particular Emphasis on Its Use in PCR Protocols

Axel Landgraf and Heiner Wolfes

1. Introduction
   Taq polymerase (EC 2.7.7.7) is a thermostable DNA-dependent DNA
   polymerase that was first isolated in 1976 from Thermus aquaticus
   strain YT-1 (ATTC # 25 104)(1). It catalyzes the template-directed
   polymerization of dNTPs at high temperatures.

5'-dGdTdGdC Taq pol. 5'-dGdTdGdCdAdCdGdAdGdAdG

3'-dCdAdCdGdTdGdCdTdCdTdC -~ 3'-dCdAdCdGdTdGdCdTdCdTdC

+dNTPs

When Taq polymerase was isolated in 1976, nobody could have known
the impact the application of Taq polymerase to the polymerase chain
reaction (PCR) would have on molecular biology (2,3). In an issue of
Science in 1989, the enzyme was dubbed molecule of the year (4).

2. Enzymology of the Taq Polymerase
   Taq polymerase constitutes only 0.01-0.02% of the total protein of
   Thermus aquaticus. The increased demand for the enzyme led to the
   cloning of the gene in E. coli. An advantage of cloning an enzyme from
   a thermophile organism in a mesophile bacterium is that, in general,
   contaminants in the enzyme preparation should not be active at a tem-
   perature optimal for the Taq polymerase (5).

From: Methods in Molecular Biology, Vol. 16: Enzymes of Molecular Biology

Edited by: M. M. Burreil Copyright ©1993 Humana Press Inc., Totowa, NJ

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