Double Quenched Probes - DQPs - NEW

metabion's double quenched probes (DQPs) are – like our DLPs - optimized for use in real-time quantitative PCR, following the underlying FRET concept, while catering to the need of efficient reduction of background noise occurring in probes longer than 25 nts.

With regard to the length of a linear hydrolysis probe used in 5´nuclease assays, two selection criteria are essential: Quenching efficiency and binding stability. Thus, sequence design is a careful compromise between both requirements.

Sometimes, it´s required to extend the probe sequence beyond the favourable 20-30 nt window, i. e. for AT-rich target sequences, in order to achieve the necessary and acceptable probe Tm suitable for best performance of the respective assay. Increasing sequence length however diminishes the quenching efficiency, resulting in elevated baseline fluorescence and poor signal-to-noise values for the designed assays.

The upper probe length restriction to 30 nts can be relaxed by introducing an internal quencher closer to the fluorescent 5´moiety, while the additional 3´quencher not only supports quenching efficiency but acts as a Polymerase inhibitor, preventing the probe from being extended upon hybridization.

Typically, the internal quencher of a DQP is placed between the 9^th and the 10^th nt downstream the 5´-fluorescent reporter. Thereby the distance between reporter and quencher is shortened and the background fluorescence is reduced.

The range of reporter-quencher combinations offered shall suit your needs for single or multiplex real-time PCR applications (see Portfolio).

Our standard DQP portfolio widely allows the introduction of “non-natural” nucleotides (base and sugar analoga) including LNA moieties. Validate your probe design through our WOP.

Like our DLPs we offer our DQPs in final yields – nmoles delivered. With this, we continue to offer a transparent and best price-performance scheme for our broad selection of DQPs:

• 5 scales based on delivered quantities tailored to your routine needs (see our Portfolio).

• Length independent guaranteed (range) of delivered quantities in nmoles for probes from 20 to 40mers. Please note that OD₂₆₀ values are a measure of total nucleotides´ optical density. Hence, neither purity nor amount of ordered substance are transparently reflected. For simplification and exemplification reasons look at the following:
  
  1 OD of the 20mer 5´CAT CGT ATT CGA TGC TAC GT 3´
  translates into approximately 5 nmol.
  
  1 OD of the 40mer 5´CAT CGT ATT CGA TGC TAC GT CAT CGT ATT CGA TGC TAC GT 3´
  translates into approximately 2.5 nmol.
  
  Therefore, a 1 OD guaranteed amount of delivered product can vary significantly, while metabion´s commitment to delivered yields in nmol for probes ranging from 20 to 40 nucleotides does not allow for ambiguity in terms of what you expect and pay for.

• metabion´s routine DQP portfolio perfectly covers the spectrum of applicable excitation and detection wavelengths, with Reporter-Quencher combinations suitable for all commonly used Real Time PCR platforms. However, do not hesitate to ask for non-listed combinations. Contact us!

• Our prices include HPLC purification as well as Mass-Check QC.

It matters what you actually get for your money!

Any question? Visit our FAQs page or contact us!

Our Standard Double Quenched Probes Portfolio

5 yield ranges* based on length independent delivered quantities from 20-40 bases.

• ≥ 5 < 10 nmol
• ≥ 10 < 20 nmol
• ≥ 20 < 30 nmol
• ≥ 30 < 50 nmol
• ≥ 50 < 70 nmol

* based on oligonucleotides of 20-40 bases in length; please note that HPLC purification and QC by Mass-Check are included

Reporter-Quencher combinations                              

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