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Bio-synthesis offers PlexorTM primers based on Promega’s PlexorTM technology from real-time qPCR to multiplex assays. This technology is based on highly specific interactions between two novel nucleotides, isoguanine (iso-dG) and 5'-methylisocytosine (iso-dC), which form a unique base pair (when incorporated in double-stranded DNA) and pair only with each other. As amplification progresses, the binding of iso-dC (linked to a flourophore) and iso-dG (linked to a quencher) bring the flourophore and quencher into close proximity, allowing the flourescence to be quenched and reduced at levels proportional to the amount of PCR product generated. The quenching effect is reversible, so melt curve analysis can be performed using this technology. Plexor are primers commonly used for Gene Expression and SNP Genotyping

All Bio-Synthesis's Plexor Primers are available at a fixed price per oligonucleotide, within the following parameters:

  • Forward primer contain an iso-dC residues and a fluorescent label at the 5' end up to 30 bases
  • Unlabeled reverse PCR primer
  • All HPLC purified
  • 100% QC by MALDI-MS, and analytical HPLC
  • Deliver lyophilized
  • TAT: 4-7 working days

Please contact technical support for assistance with design of Plexor Primers

Benefit of Using PlexorTM Primers:

  • Simple primer design
  • Does not require a separate probe
  • Powerful multiplexing capability

Choosing Scorpions Probes for:

  • Gene Expression
  • SNP Genotyping

How does PlexorTM Primers Work?

PlexorTM Primer technology is a unique real-time PCR chemistry based on the specific interaction between two modified nucleotides: iso-dC and iso-dG. These two modified nucleotides only pair with each other when forming double-stranded DNA. Plexor assays incorporate iso-dC residue and a fluorescent label on the 5' end of the forward primer while the reaction mix includes DABCYL-labeled iso-dG, along with unlabeled reverse primers.

The first step involves heating to denature the double-stranded target DNA into single-stranded DNA. During the second step, the forward primer containing the 5' modified iso-dC and fluorophore anneals to the target DNA and is extended by polymerase. In the next cycle, the resulting double-stranded DNA is melted and the unlabeled reverse primer anneals and is extended by polymerase. When the polymerase encounters the 5' iso-dC, a modified iso-dGTP is added instead of a standard guanine. The binding of fluorophore linked iso-dC and quencher linked iso-dG is brought into close proximity, allowing the fluorescence to be quenched, resulting in a reduction in fluorescent signal.

Plexor Primer

Plexor Primer for Gene Expression and Genotyping

If you can't find the dye and quencher combination listed below, please contact us

Forward PlexorTM Primer Item No Deliver Yields (dual HPLC purified) Price


No. of nmole

No. of µg

5' FAM + 1 isodC modified base PLEP-FAM-02 0.6 2 18.5 $195.00
PLEP-FAM-05 1.5 5 46 $ 265.00
5' TAMRA + 1 isodC Modified base PLEP-TAM-02 0.6 2 18.5 $ 280.00
PLEP-TAM -05 1.6 5 46 $ 340.00
5' ROX + 1 isodC Modified base PLEP-ROX-02 0.5 2 18.5 $ 280.00
PLEP-ROX-05 1.6 5 46 $ 340.00
5' HEX + 1 isodC Modified base PLEP-HEX-02 0.6 2 18.5 $ 225.00
PLEP-HEX-05 1.5 5 46 $ 295.00
5' Texas Red® + 1 isodC Modified base PLEP-TEX-02 0.6 2 18.5 $ 295.00
PLEP-TEX-05 1.5 5 46 $ 340.00
5' Cy5® + 1 isodC Modified base PLEP-CY5-02 0.6 2 18.5 $ 250.00
PLEP-CY5-05 1.5 5 46 $ 310.00

PlexorTM Unlabeled Companion Primers

Reversed PlexorTM Primer Item No Deliver Yields (HPLC purified)
OD260 No. of nmole No. of µg Price
No Label - no isodC reverse primer PLEP-REV-10 3 OD 10 95 $ 20.00

PlexorTM Primers Human Control Gene Primer Sets

Deliver Yields (HPLC purified) Item No
PlexorTM Human GAPHD Primer Set, 5' Texas Red $108.00
PlexorTM Human GAPDH Primer Set, 5' HEX $108.00
PlexorTM Human GAPDH Primer Set, 5' CAL Fluor Organge 560 $108.00
PlexorTM Human GAPDH Primer Set, 5' CAL Fluor Organge Red 610 $108.00
PlexorTM Human GAPDH Primer Set, 5' CAL Fluor Quasar 670 $108.00
PlexorTM ß-Actin Primer Set, 5' Texas Red $108.00
PlexorTMß-Actin Primer Set, 5' HEX $108.00
Pre-mixed PlexorTM Control Gene Primer Set contains 0.5 nmoles of the PlexorTM Primer and an unlabeled companion reverse primer.


In order to ensure that there is no background fluorescence, 100% of the dual labeled probes are purified by single or dual rp-HPLC and ie-HPLC as a standard protocol for all dual–labeled probes which give 90-97% purity. Depending on the type of the probes, one or two purification may performed to ensure the highest purity level

Quality Control

All dual labeld probes are quality checked by MALDI-TOP Mass spectrometry , analytical HPLC and analyze by Fluorometric Scan (ABS/EM) . In addition, the signal-to-background ratio is measured against a target sequence for all molecular beacons.

Delivery times

3-5 Working days



Shipping conditions

Room temperature

Storage conditions  

-20 oC to -70 oC

Oligonucleotides are stable in solution at 4oC for up to 2 weeks. Properly reconstituted material stored at -20oC should be stable for at least 6 months. Lyophilized DNA (when kept at -20oC) in a nuclease-free environment should be stable for year


Quality control:

Every oligo is quality checked by MALDI-TOF mass spectrometry, electrospray ionization mass spectrometry (ESI-MS), capillary electrophoresis (CE), and/or polyacrylamide gel electrophoresis (PAGE).


Fully deprotected and desalted. Purified by PAGE or RP-HPLC


LightCycler probes 15 to 40 mers (optimal length: 20 to 30 mers)
Dual-labeled fluorogenic probes: 15 to 40 mers
Molecular Beacons 15 to 40 mers
Scorpions probes 30 to 60 mers (uni-probe)
15 to 45 mers (bi-probe)
Plexor up to 30 mers


Phosphodiester bond


Delivered as dried-down product in opaque tubes

Turn-around time:

Turn-around time
LightCycler probes 4 to 5 working days
Dual-labeled fluorogenic probes: 5 to 6 working days
Molecular Beacons 5 to 6 working days
Scorpions probes 7 to 10 working days

Turn-around time is dependent upon successful QC validation and does not include shipping time.

Storage and stability:

See information on our oligos: storage recommendations


Shipped by mail or express delivery, dry, in individual, opaque tubes

Technical Documentation:

Oligonucleotides are delivered with an OligonucleotideTechnical Data Sheet, which includes oligonucleotide name, sequence, concentration, precise quantity in OD and nmols, Tm, MW, length, extinction coefficient and purification data.

Additional Services:
  • Probe design services
  • High-throughput screening formats (microplates, etc)
  • Aliquoting

Additional services may increase turn-around time


Please contact your local Bio-Synthesis representative


On-line (contact us), by email ( or fax

Ordering & Contact Information

  • Please contact us for additional information or send an email to
  • You may also request an online quote.
  • To contact us by phone, please call 1-972-420-8505 or Fax at 1-972-420-0442
  • Orders may be placed using a purchase order (PO) or by credit card through our secure online ordering system.
  • When using a credit card ( creditcard ) it will be billed under "Bio-Synthesis, Inc."