PlexZyme™ technology offers high performance and reliable qPCR detection and is  the driver behind the entire SpeeDx product portfolio. During PlexZyme™ qPCR, primers amplify target nucleic acid sequences and produce amplicons which serve as a template for PlexZyme™ formation. Once the partzymes have assembled into PlexZymes™, universal probes bind and enzymatic cleavage of the probes between fluorophore and quencher dye pairs generates fluorescence. Changes in fluorescence allow detection and/or quantification of the target nucleic acid in real time.



  • Can detect < 10 copies of target


  • Good dynamic range from 106 to 10 copies

Highly Specific

  • Specificity is determined by 4 binding events of the 2 primers and 2 partzymes to the amplicons


  • Probe design is independent of target sequence, allowing for the use of a suite of well-characterised universal probes.

PlexZymes™ (formerly known as MNAzymes) are catalytic DNA complexes which assemble in the presence of target and cleave universal probes. The bi-specificity of the PlexZyme™ activity minimises the chance of false positive signals, and the use of universal probes allow for robust and consistent reaction performance.

An active PlexZyme™ is made up of two DNA oligonucleotide components called partial enzymes or “partzymes”. Each partzyme comprises only part of a catalytic core flanked by a sensor arm which binds to a target sequence, and a substrate arm which binds to a universal probe.
Partzymes are inherently inactive; however, when bound adjacently on a target, they form active PlexZyme™.
PlexZymes™ catalyse the cleavage of universal probes, resulting in fluorescence signal that can be monitored in real time.

Multiplexing Accelerated

PlexZyme™ qPCR has many attributes which make it superior for multiplexing. A series of well-characterized universal reporter probes can be incorporated into multiplex assays allowing analysis of several targets simultaneously. The flexible nature of the partzymes means that new targets can be linked to existing probes simply by synthesising new partzymes with sensor arms tailored to the new target, and substrate arms to one of the series of unique universal probes.

Principle Of Multiplexing With PlexPCR™

PlexZymeMultiplexing with SpeeDx technology PlexPCR which can maximise the outputs of qPCR instruments.

In a multiplex reaction, the universal probes are labelled with different fluorophores so that fluorescence signal corresponding to detection of each target sequence can be monitored simultaneously in real time. The highly multiplex nature of PlexZymes™ can maximise the outputs of qPCR instruments.


Mokany E., Tan Y.L., Bone S.M., Fuery C., Todd A.V., 2013. MNAzyme qPCR with superior multiplexing capacity. Clin. Chem. 59(2); 419-426
Link | Article | Supplementary Information

Mokany E., Bone S.M., Young P.E., Doan T.M., Todd A.V., 2010. MNAzymes are a versatile new class of nucleic acid enzymes which can function as biosensors and molecular switches. J. Am. Chem. Soc. 132(3); 1051-1059
Link Article | Supplementary Information