Z-domain ligands engineered for alkaline stability, secreted from E. coli and purified in the EU. Pick the ligand, the stability level and the immobilisation handle — from a 10 mg evaluation vial to kilogram supply.
Ligand, stability level, immobilisation handle, quantity. Mass, pI and the target purity follow from the configuration and are shown on the right.
Wild-type Protein A is a different tool, not a weaker one — it retains Fab/VH3 binding that the engineered scaffolds have largely lost. Choose it for Fab capture and discovery work, and an engineered scaffold where repeated caustic cleaning decides the resin lifetime. Cysteine and azido variants share the identical binding domain as their base ligand — only the handle changes.
| Part number | Ligand | Stability | Handle | Immobilisation | Stabilisation level | Fab / VH3 | Smallest format |
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How to read the stabilisation level. The bars show how many alkali-stabilising substitutions the construct carries by design — they are not a measured capacity retention, and they are not comparable across ligands. Head-to-head caustic cycling data across the portfolio is in preparation; ask us for the current status before you design around a stability assumption.
Buy a finished affinity product and the support and the coupling chemistry come decided. We supply the ligand alone — bead, monolith, membrane or nonwoven, the matrix, the ligand density and the coupling route stay yours.
The cysteine variants give thiol-directed attachment on epoxy or maleimide surfaces. The azido variant carries a non-canonical amino acid for strain-promoted click chemistry — one defined attachment point per ligand, nothing random.
The 10 mg you evaluate is the same construct and the same process we scale to kilograms. No re-qualification because the supply grade came from a different cell line.
We keep one internal reference matrix so that binding data means something — it exists to characterise the ligand, never for resale. Your matrix, your ligand density and your process stay yours, and we do not compete with the product you build on top of us.
Expression, purification and fill happen inside the EU. The ligand is secreted from E. coli rather than released by cell lysis, which keeps host-cell protein and nucleic acid out of the feed stream before purification even starts — and keeps a European supply route for a reagent class that is otherwise sourced almost entirely outside the EU.
If your resin ends up in a GMP process, someone will ask about batch comparability and change control. Talk to us about lot history and how we notify you of process changes before you commit to a ligand — those questions get harder to answer later.
Mass, pI and the stability level are shown in the configurator above. Everything measured per lot is on the certificate of analysis.
Every lot ships with a certificate of analysis covering appearance, pH, concentration, nucleic acid content, identity, purity, endotoxin and bioburden, with the SE-HPLC and SDS-PAGE traces for that lot. See an example certificate of analysis (PDF, 221 kB)
enGenes offers a growing portfolio of Protein A affinity ligands for the development of chromatography resins used in antibody purification. The portfolio includes different ligand variants designed to address application-specific requirements, including alkaline stability and alternative immobilisation handles. Explore our product range or talk to our team to identify suitable candidates for your application.
The right ligand depends on your target molecule, chromatography resin design, coupling chemistry and process conditions. enGenes offers different Protein A ligand variants to support specific application requirements. If you are unsure which ligand to select, contact our team to discuss your application and identify suitable candidates for evaluation.
Yes. enGenes can provide Protein A ligand samples for evaluation, subject to product availability and the applicable supply terms. Evaluation allows you to assess ligand performance in your own application, including comparison against an established benchmark. Contact us to discuss sample quantities, product availability, pricing and options for larger-scale supply.
Protein A ligands differ in their resistance to alkaline conditions, which are commonly used during cleaning-in-place (CIP) of chromatography resins. A highly alkaline-stable ligand may help maintain binding performance over repeated cleaning cycles, depending on the process conditions and resin formulation. enGenes offers standard and highly alkaline-stable Protein A ligand variants to support different purification and cleaning requirements.
The 10 mg and 100 mg evaluation formats carry a list price and are ordered through the enquiry basket. For other quantities, request a quote and we will get in touch.
Evaluation formats ship from stock where available. Larger quantities are made to order — the quote states the schedule.
Yes. Custom ligands, alternative handles and non-canonical amino acids at defined positions are part of the expression platform. We also co-develop ligands with resin, monolith and membrane manufacturers.
The construct and the process do not change between the evaluation vial and supply scale. For volumes beyond our own capacity we manufacture through a GMP-experienced European contract partner under a defined transfer package, so the supply route is documented rather than improvised. The quote states which route applies.
All ligands ship in liquid format, cold. Shipping outside the EU includes the customs documentation.