PUREfrex® kit is a reconstituted in vitro Coupled Transcription/Translation Systems, completely different from an E.coli extract S30 system.

PUREfrex® is a series of newly developed reconstituted cell-free protein synthesis reagent based on PURE system technology invented by Professor Takuya Ueda in the University of Tokyo. This reaction system consists of proteins, ribosome, amino acids and NTPs only (Ref. 1, 2). Those proteins are necessary for transcription, translation and energy regeneration. The proteins and ribosome are highly purified individually and assembled together to constitute the protein synthesis system. This system’s most unique point is RECONSTITUTED system by assembling translation related factors only. By this unique character, you may adjust the composition of reaction mixture as you like and may not have to consider serious background for your downstream application.

By improving the purification process of components in PUREfrex®2.0 kit, contamination of RNase and β-galactosidase are greatly reduced, in addition to that, lipopolysaccharide (LPS) is also reduced around 0.1 EU per 1 µL of reaction mixture. All proteinous components of PUREfrex® kit have no tags for purification and detection. It allows to fuse your protein with any tag to purify the product.

Depend on your protein’s property, we have supplements to add to PUREfrex® kit. Molecular chaperones, DnaK Mix or GroE Mix, are for improving folding and solubility. DS supplement is for making disulfide bonds. Depending on each protein, adding those supplements to PUREfrex® kit helps effective translation and folding simultaneously.

Molecular chaperones such as hsp70 (e.g. E. coli DnaK) assist the correct folding of the newly synthesized proteins. Because PUREfrex® does not contain any molecular chaperones, some proteins may have difficulty in forming the correct conformation and be insoluble after synthesis. In such cases, molecular chaperones could contribute to make them soluble and active.

For some proteins, such as secretory proteins, formation of a disulfide bond is important for their stability or activity. Disulfide bonds are usually formed by the oxidation of sulfhydryl groups (SH-) of adjacent cysteine residues. Therefore, oxidized environment is necessary to form a disulfide bond. Additionally, disulfide bond isomerase (e.g. E. coli DsbC), which can catalyze the disulfide bridge exchange, is also necessary to form a correct paring of cysteines.

Ref)1. Shimizu et al. (2001) Nat. Biotechnol., vol. 19, p. 751
2. Shimizu et al. (2005) Methods, vol. 36, p. 299


Please visit our web site to download our posters for more details.

For preparation of following proteins

prokaryotic protein
eukaryotic protein
membrane protein
protein containing disulfide bonds
protein containing unnatural amino acids
… etc.

For basic research in protein science

Folding of protein after synthesis

For in vitro display

Ribosome display
mRNA display

Kits and Order

Please visit our Lineup web site for our product lineup and how to order.


PUREfrex® is developed for in vitro research only. PUREfrex® should not be used for the therapy, diagnostic or administration to animals including human and should not be used as food or cosmetics etc. To avoid the contamination of nuclease, nuclease-free-treated water, reagents and materials should be used. We also recommend wearing gloves and mask.
“PUREfrex® is Registered in U.S. Patent and Trademark Office”