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Whether your protein is from bacterial, mammalian or baculovirus expression, our scientists will assist you on the strategy for a customized approach to your protein and purity needs. Marin Biologic’s extensive experience in biochemistry includes the production, purification to homogeneity, and characterization of native proteins isolated from cells and tissue as well as recombinant proteins (including the cloning step).

Biopharmaceuticals are composed of protein or fragments of proteins, with mimetics as small peptides that “mimic” the functional active site of the protein. Early efforts with protein activities often require a purified or enriched preparation. Ultimately, a homogeneously purified protein is necessary for final characterization and formulation.

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MarinBio’s professionals have years of experience with protein production, purification and characterization. Our scientists are trained to develop and implement strategies for various proteins, glycoproteins, peptides, including as follows:

  • Recombinant protein production – bacterial, Baculovirus insect, yeast, mammalian
  • Native protein purification, from plasma, tissue extract, etc.


HEK 293 cells were adapted for suspension culture and transfected with a DNA plasmid. After 4 days the supernatant media was harvested and the expressed recombinant protein purified by binding to a Protein L column. Elution of the protein was followed by absorbance at 280nm. Characterization of the protein pool was performed on SDS-PAGE, and the purified protein showed the expected molecular weight.


  • Classical chromatography (including size exclusion, ion exchange, etc.) one-step affinity chromatography, tag-based protein purification, bulk protein precipitation (including salt precipitation)
  • Western blot (detection of contaminants) and ELISA for specificity and quantitation
  • Purity and size of proteins by SDS-PAGE chromatography (detection of potential contaminants, aggregates, etc., see Figure below), N-terminal amino acid assessment

Reducing SDS-PAGE analysis of an antibody drug at 2 and 4ug per well. Under these reducing conditions, the antibody is separated to the heavy chain (50 kdaltons) and light chain (25kdaltons).


  • Protein size, charge, stability, Eastern blots for post-translational modifications
  • Western blot, ELISA
  • Thermal and other stability, isoelectric point (pI)
  • Binding to target, bioassay
  • Enzyme and protein assays
  • Conjugation to carrier proteins/reagents
  • Biotinylation
  • Covalent binding to supports (resins, gels)