Cell-free expression works best for proteins that are toxic to cells, form inclusion bodies under standard conditions, need rapid screening of multiple variants, or require non-canonical amino acid incorporation.
Cloning & Expression Systems
Cell-free Protein Expression Kits
Cell-free protein expression kits for rapid protein production without cell culture
These kits take you from DNA template to protein in a few hours at the bench. You skip the delays of cell culture, transformation, and selection. The reaction combines the transcription and translation machinery you need to make protein directly in a test tube, with no cells, transformation steps, or culture media.
Cell-free expression suits proteins you find difficult to produce in living cells. Toxic proteins that impair cell growth are one example. Integral membrane proteins with poor solubility or multiple transmembrane domains are another. So are proteins that need non-canonical amino acid incorporation for labelling or chemical modification. The open-extract format also lets you screen multiple construct variants in parallel, using linear PCR products without a cloning step. Reactions are typically microlitre scale and complete within hours.
Kit selection depends on your target protein type, your template format, the scale and throughput you need, and what you will do with the protein afterwards.
Choose your cell-free expression system
- Antibodies or disulfide-bonded proteins: use the myTXTL Antibody Kit. It is optimised for correct disulfide bond formation in a cell-free reaction.
- All other proteins (soluble, membrane, toxic, or difficult in cells): use myTXTL Pro, a versatile E. coli-based cell-free system for rapid expression and screening.
Both kits work with plasmid DNA for higher yields. Both also work with linear PCR templates for fast construct screening in small-scale reactions.
Parent category: protein expression systems
Applications
Toxic protein synthesis
Cell-free reactions have no living host, so you can express proteins that arrest growth or kill cells in vivo, without selective pressure.
Membrane protein production
You can make integral membrane proteins cell-free, even with poor solubility or several transmembrane domains, supplemented with detergents, lipids, or nanodiscs.
Rapid construct screening
Linear PCR templates skip cloning and transformation, so you can screen tag position, truncation, or mutation variants in parallel within hours.
Non-canonical amino acid incorporation
Cell-free systems allow site-specific incorporation, which supports bioorthogonal chemistry, cross-linking studies, and protein labelling.
Antibody and disulfide-bonded proteins
The myTXTL Antibody Kit gives correct disulfide bonding cell-free, a route to functional antibody fragments without mammalian culture.
Synthetic biology circuit prototyping
Test genetic circuits, promoters, and regulatory elements cell-free before moving into cells, read out with fluorescent reporters for a fast result.
Product Catalog
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myTXTL Cell-free Expression
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Frequently asked questions
Yes, provided the PCR product contains a suitable promoter upstream of the coding sequence. It also needs a ribosome-binding site compatible with the extract. Linear template design also has specific sequence requirements at the 5' and 3' ends, including protection against nuclease degradation, as set out in Arbor's myTXTL documentation and its accompanying IDT technical note. Linear templates are convenient for construct screening without a cloning step. However, they typically give lower yields than circular plasmids.
Clarify the reaction by centrifugation to remove aggregates. Then apply an activity assay or binding assay to the supernatant. For enzymes, a substrate conversion assay is straightforward. For binding proteins, an ELISA or pull-down against a known partner confirms folding. Run a no-DNA control reaction in parallel to distinguish protein-specific signal from extract background.
Yield depends on the extract type, the specific protein, and the reaction conditions. Confirm expected yield ranges with the kit documentation or BioCat before you plan your experiment. This is particularly important if downstream applications need a minimum amount of protein.
Product catalogs
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