AmpliTaq Gold
Definition
A chemically modified hot-start form of Taq polymerase (Applied Biosystems) that is inactive at room temperature and requires a 10-11 minute activation hold at 95°C, preventing non-specific pre-amplification.
- Manufacturer
- Applied Biosystems
- Enzyme type
- Chemically modified hot-start Taq
- Activation hold
- 10-11 minutes at 95°C
- Room-temperature state
- Inactive
Common questions
What problem does the hot-start design solve?+
Ordinary Taq polymerase can extend mispriming events during reaction setup at room temperature, producing non-specific products and primer-dimers before thermal cycling even begins. Keeping the enzyme chemically blocked until the initial denaturation step avoids this.
Why is the activation time built into the PCR cycling program a fixed value?+
The 10 to 11 minute hold at 95°C is calibrated to reliably reverse the chemical modification and fully activate the enzyme; shortening it risks incomplete activation and reduced yield, while it is not typically extended further without reason.
Related terms
- A-Addition
- The non-templated addition of a single adenine nucleotide to the 3' end of PCR products by Taq polymerase, exploited in forensic STR...
- Annealing Temperature
- The reduced temperature (50-65°C) at which primers hybridise to single-stranded template. Determined by primer Tm; set to balance specificity against yield.
- Denaturation
- The separation of double-stranded DNA into two single strands by disrupting the hydrogen bonds between base pairs. In PCR, denaturation is achieved...
- Extension
- The PCR step at ~72°C at which thermostable DNA polymerase synthesises a new complementary strand from each primer, using dNTPs in the...
- Hot-Start Polymerase
- Any Taq formulation (antibody-mediated, chemically modified, or aptamer-blocked) that is inactive below ~60°C, preventing non-specific amplification during reaction setup.
- Melting Temperature (Tm)
- The temperature at which half of a primer-template duplex population is dissociated. Depends on primer length, GC content, and nearest-neighbour stacking interactions.
- Negative Amplification Control
- A no-template reaction well run alongside case samples; any amplified peak indicates reagent contamination or analyst-introduced contamination during setup.
- Uni-Directional Workflow
- The physical principle governing forensic DNA laboratory layout: personnel and materials move from pre-PCR to post-PCR zones only, preventing high-copy-number amplified products...