Protein purification
A purification train is a series of resins, not one. Capture on an affinity ligand matched to your tag or native target, polish by charge on an ion exchanger if you need higher purity, and finish with size-exclusion to exchange buffer and remove aggregate, bulk resin or prepacked column, your call.
Capture
Pull your target from clarified lysate or supernatant on an affinity resin: Protein A/G/L for antibodies and Fc fusions, Ni-NTA or cobalt-IDA for His-tagged recombinant protein, glutathione agarose for GST fusions, or amylose for MBP fusions.
Polish by charge
If capture alone doesn't hit your purity spec, run a second pass on an anion (Q, DEAE, ANX) or cation (SP, CM) exchanger, chosen by your target's isoelectric point relative to your running buffer pH.
Final polish / buffer exchange
Size-exclusion resin separates by hydrodynamic radius, use it last to remove aggregate and high/low molecular weight contaminants while simultaneously exchanging into your final storage buffer.
Confirm purity
Run reduced and non-reduced SDS-PAGE against a molecular weight ladder to confirm single-band purity and check for degradation or aggregation before you commit the prep to a downstream assay.
Ni-NTA Agarose, 6% cross-linked
Protein A Agarose, small bead (columns)
Protein A Agarose, large bead (spin / gravity)
Protein A Magnetic Beads
Every product below is pulled live from the catalog, not hand-curated marketing copy.
How do I pick an affinity ligand?
Match the ligand to what's actually on your protein: Ni-NTA or cobalt-IDA for a His6 tag, Protein A for IgG Fc (especially human/rabbit), Protein G for a broader IgG species range, Protein L for kappa light chains, glutathione for GST, amylose for MBP, and Strep-Tactin for a Strep-tag II.
Ni-NTA or cobalt?
Ni-NTA binds His-tagged protein more tightly and gives higher dynamic binding capacity; cobalt-IDA binds more weakly but more selectively, so it co-purifies fewer native histidine-rich E. coli proteins. Use cobalt when a Ni-NTA prep shows persistent background bands.
Bulk resin or a prepacked column?
Bulk resin is cheaper per mL and lets you pack a custom bed volume for gravity or FPLC use; a prepacked column is ready to plumb straight into an FPLC/AKTA system with a reproducible bed height and no packing variability. Prepacked is worth the premium for repeat runs on the same system.
What does dynamic binding capacity (DBC) actually tell me?
DBC is the mass of target the resin binds at a given flow rate before breakthrough, reported here at 10% breakthrough on the datasheet. Size your column against DBC, not total ligand density, or you'll lose product to the flow-through on a fast run.
More application workflows, curated products, and category links live on the applications hub. Datasheets, SDS, and Certificates of Analysis are under Documents.