chemistry

Polymerase

Polymerase is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Polymerase rather than just read about it. In short: In biochemistry, a polymerase is an enzyme (EC 2.7.7.6/7/19/48/49) that synthesizes long chains of polymers or nucleic acids. DNA polymerase and RNA polymerase are used to assemble DNA and RNA molecules, respectively, by copying a DNA template strand using base-pairing interactions or half ladder replication.

Key takeaways

Polymerase belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Polymerase to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Polymerase from memory before moving on to harder problems.

Reference excerpt

In biochemistry, a polymerase is an enzyme (EC 2.7.7.6/7/19/48/49) that synthesizes long chains of polymers or nucleic acids. DNA polymerase and RNA polymerase are used to assemble DNA and RNA molecules, respectively, by copying a DNA template strand using base-pairing interactions or half ladder replication. A DNA polymerase from the thermophilic bacterium, Thermus aquaticus (Taq) (PDB 1BGX Archived 2007-07-04 at the Wayback Machine, EC 2.7.7.7), is used in the polymerase chain reaction, an important technique of molecular biology. A polymerase may be template-dependent or template-independent. Poly-A-polymerase is an example of template independent polymerase. Terminal deoxynucleotidyl transferase is also known to have template independent and template dependent activities.

By function

DNA polymerase (DNA-directed DNA polymerase, DdDP) Family A: DNA polymerase I; Pol γ, θ, ν Family B: DNA polymerase II; Pol α, δ, ε, ζ Family C: DNA polymerase III holoenzyme Family X: Pol β, λ, μ Terminal deoxynucleotidyl transferase (TDT), which lends diversity to antibody heavy chains. Family Y: DNA polymerase IV (DinB) and DNA polymerase V (UmuD'2C) - SOS repair polymerases; Pol η, ι, κ Reverse transcriptase (RT; RNA-directed DNA polymerase; RdDP) Telomerase DNA-directed RNA polymerase (DdRP, RNAP) Multi-subunit (msDdRP): RNA polymerase I, RNA polymerase II, RNA polymerase III Single-subunit (ssDdRP): T7 RNA polymerase, POLRMT Primase, PrimPol RNA replicase (RNA-directed RNA polymerase, RdRP) Viral (single-subunit) Eukaryotic cellular (cRdRP; dual-subunit) Template-less RNA elongation Polyadenylation: PAP, PNPase

By structure Polymerases are generally split into two superfamilies, the "right hand" fold (InterPro: IPR043502) and the "double psi beta barrel" (often simply "double-barrel") fold. The former is seen in almost all DNA polymerases and almost all viral single-subunit polymerases; they are marked by a conserved "palm" domain. The latter is seen in all multi-subunit RNA polymerases, in cRdRP, and in "family D" DNA polymerases found in archaea. The "X" family represented by DNA polymerase beta has only a vague "palm" shape, and is sometimes considered a different superfamily (InterPro: IPR043519). Primases generally don't fall into either category. Bacterial primases usually have the Toprim domain, and are related to topoisomerases and mitochondrial helicase twinkle. Archae and eukaryotic primases form an unrelated AEP family, possibly related to the polymerase palm. Both families nevertheless associate to the same set of helicases.

Modification of activity Scientists have modified the activity of nucleic acid polymerases in many ways, from rational design to directed evolution, to achieve changes from incremental tweaks like higher speed/accuracy/thermostability or major shifts such as conversion of template and product types.

Nucleic acid types All known natural reverse transcriptases evovled from an ancestor that has no proofreading ability, causing a low fidelity. In 2016, scientists successfully used directed evolution to modify the proofreading Thermococcus kodakarensis DNA-directed DNA polymerase into what they call a reverse transcribing xenotranscriptase (RTX). This new enzyme is able to copy from and proofread with RNA and DNA templates. It is expected to improve the accuracy in RNA sequencing and other forms of RT-PCR. It was commercialized some time before April 2018. In 2022, selective mutagenesis converted a Kod DNA polymerase into one that produces α-l-threofuranosyl nucleic acid or threose nucleic acid (TNA). This result has been improved in 2024 and 2025 using HR-accelerated directed evolution, yielding several enzymes with near-natural speed and fidelity. In 2025, scientists used directed evolution, accelerated by homologous recombination (HR), to change a DNA polymerase into an RNA polymerase. It is able to perform transcription quickly (3 nt/s) and accurately (>99%). It is also a somewhat "universal" polymerase, being also capable of RNA-directed DNA production (reverse transcription) and chimeric DNA–RNA amplification.

See also Central dogma of molecular biology Exonuclease Ligase Nuclease PCR PARP Reverse transcription polymerase chain reaction RNA ligase (ATP)

References

External links

Illustrations

Worked examples

Example 1 — a first encounter with Polymerase

Start with the simplest possible case. Write down what Polymerase claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Polymerase before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Polymerase ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Polymerase

In research: Polymerase appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Polymerase in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Polymerase is common in secondary-school and first-year university syllabi. It links to neighbouring topics EC 2.7.7, Enzymes, so understanding it makes those chapters shorter.
In everyday life: Look for Polymerase outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Polymerase in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Polymerase means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Polymerase out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Polymerase in simple terms?

Why does Polymerase matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Polymerase?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Polymerase.