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Polymerases

Polymerases are enzymes which can be found in all living organisms. They catalyze the synthesis of long chains or polymers of nucleotides, subunits of nucleic acids the building block of DNA. They are used in the multiplication of genetic information (DNA) e.g. during replication, a process prior to cell division. In this way, genetic information is transmitted from generation to generation. Additionally they are crucial for the first steps of protein biosynthesis, the production of proteins within a cell.

Polymerases are used to assemble DNA and RNA molecules and usually work in pairs. They link specific sequences of nucleotides to chains using base-pairing interactions. This sequences is determined by another chain of nucleic acids which is used as template (fig. 1). Depending on type of template and product (RNA or DNA) one can distinguish between following polymerases:


DNA polymerases adds nucleotides to the 3' end of a strand of DNA.
fig 1. DNA polymerases adds nucleotides to the 3' end of a strand of DNA.


Type Template → Product Function
DNA-dependent DNA-Polymerase DNA → DNA Replication
RNA-dependent DNA-Polymerase RNA → DNA Reverse transcription
DNA-dependent RNA-Polymerase DNA → RNA Transcription
RNA-dependent RNA-Polymerase RNA → RNA Replication of some RNA-viruses


Taq polymerase

Taq polymerase is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated. Its name is often abbreviated to Taq Pol or simply Taq. It is frequently used in the polymerase chain reaction (PCR), a method for greatly amplifying the quantity of short segments of DNA.

T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq's optimum temperature for activity is 75–80 °C, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at 72 °C.

A problem which occurs when working with Taqs is the lack of 3' to 5' exonuclease proofreading activity which lowers the replication fidelty by a big margin. Originally its error rate was measured at about 1 in 9,000 nucleotides. In comparison DNA-Polymerase which can be found in the humand body show mistakes about one in every billion base pairs copied. They proofread after copying so that misplaced base pairs can be corrected. This preserves the integrity of the original DNA strand that is passed onto the daughter cells. And lowers the mutation rate.

Our 3 Top Taq Polymerases:

Taq Polymerase Description Product details
Taq DNA Polymerase
ABIN1536547
Terminal transferase activity: Taq DNA Polymerase has terminal transferase activity, which results in the addition of a single nucleotide (adenosine) at the 3' end of the extension product. High purity: No contamination activity has been detected in standard test reactions. Show details
Diamond Taq DNA Polymerase
ABIN3188324
Diamond Taq® polymerase is a highly thermostable enzyme produced and purified from recombinant Escherichia coli bacterium containing the Thermus aquaticus DNA Polymerase gene. Higher sensitivity. Ultra-low bioburden. Ultra-low residual DNA content Show details
Green Taq DNA Polymerase
ABIN1536228
Green Taq DNA Polymerase is designed to increase the stability of the Taq enzyme for more convenient transport and applications. The polymerase (1000 U) is designed for 400 rxns if 2.5 U are used per 50 µL PCR reaction. Show details

Pfu Polymerase

Pfu DNA polymerase is an enzyme found in the hyperthermophilic archaeon Pyrococcus furiosus. Pfu DNA polymerase has superior thermostability and proofreading properties compared to Taq DNA polymerase. Unlike Taq DNA polymerase, Pfu DNA polymerase possesses 3' to 5' exonuclease proofreading activity, meaning that as the DNA is assembled from the 5' end to 3' end, the exonuclease activity immediately removes nucleotides misincorporated at the 3' end of the growing DNA strand. Consequently, Pfu DNA polymerase-generated PCR fragments will have fewer errors than Taq-generated PCR inserts.

Commercially available Pfu typically results in an error rate of 1 in 1.3 million base pairs and can yield 2.6% mutated products when amplifying 1 kb fragments using PCR. Therefore it is useful in PCR reactions which need sequenz precise DNA amplificates. Using Pfu DNA polymerase in PCR reactions also results in blunt-ended PCR products. This can be used for easier cloning. However, Pfu is slower and typically requires 1–2 minutes per cycle to amplify 1kb of DNA at 72 °C (compaired to less than 10 seconds using Taq). This is why for most PCR application the cheaper Taq polymerase is still the tool of choice. Conjunction of Pfu and Taq polymerase obtain the fidelity of Pfu with the speed of Taq polymerase activity.

Our 3 Top Pfu Polymerases:

Pfu Polymerase Description Product details
PFU DNA Polymerase
ABIN411757
Pfu DNA Polymerase for accurate and consistent performance in PCR. Pfu DNA Polymerase, combined with optimized buffer for high-fidelity and yield, provides the most accurate and consistent performance in PCR.enzyme demonstrates up to 20 folds greater accuracy than other similar enzyme in the market. Show details
FastPfu DNA Polymerase Enzyme
ABIN2952634
Functional absence of double and single stranded endonuclease activity. FastPfu DNA Polymerase is a fast, high fidelity and high processivity hot start DNA polymerase. The extension rate is about 2-4 kb/min. Amplification of genomic DNA fragment up to 15 kb. Amplification of plasmid DNA fragment up to 20 kb. Show details
PFU DNA Polymerase
ABIN2190160
Recombinant Pfu DNA Polymerase. Show details

Polymerases at genomics-online.com

Product Hot start? Speed
(Kb per minute
Processivity
(Kb)
Error rate
(10^-6)
5'-3' exo? 3'-5' exo? GC content
(%)
Annealing temp
(°C)
Template
(RNA/ DNA)
Proof- reading? Specifity/ Fidelity* Key Features Application/ Misc
Taq DNA Polymerase
(ABIN411754)
1 Kb Up to 6 Kb NA NA NA 50-65°C,for 60 sec DNA */1X PCR and primer extension reactions at elevated temperatures.
PFU DNA Polymerase
(ABIN411757)
< 20 Kb < 20,kb, 3’ → 5’exonuclease (proofreading) activity NA NA NA 50-65°C,for 60 sec,ec DNA ***/20X High-fidelity and High PCR. Gene synthesis.
PCR or Primer extension requested High fidelity.
Blunt-end PCR Cloning or mutagenesis requested high fidelity.
Ready™ DNA Polymerase 1Kb Up to 6 Kb No detectable 3’ - 5’ proofreading exonuclease activity low,5’ to 3’exo activity. NA NA 45 - 72°C for 30 sec DNA **/1X Robust PCR performance with great reproducibility.
High sensitivity.
PCR products amplified up to 6 kb in length with Taq DNA Polymerase contain a single base (A) 3’ overhang.
Routine PCR amplification of DNA templates up to 6 kb.
Suitable for a wide range of PCR assays.
TA cloning.
Robust Ready™ DNA Polymerase 1 Kb Up to 6 Kb 7.5 x10-6 per nucleotide per cycle NA 45 - 72°C for 30 sec DNA **/5X Improved sensitivity and fidelity compared to conventional Taq DNA Polymerase.
Robust and consistent performance across a wide range of templates.
An economical alternative to Taq DNA Polymerase.
PCR products contain a mixture of blunt ends and single base (A) 3’ overhang.
Routine PCR amplification of DNA templates up to 6 kb.
Suitable for a wide range of PCR assays.
TA cloning.

Specificity/Fidelity* as compared to Taq DNA Polymerase