Posttranslational Modifications (PTM)

Relevance of posttranslational modifications

As even subtle changes of posttranslational modifications (PTM) of biopharmaceutical proteins might have significant impact on safety and efficiacy of the products, analysis of such posttranslational modifications is of utmost importance, especially but not only in the case of biopharmaceutical proteins claiming to be similar with an already licensed reference product.

Assessment of posttranslational modifications

The analysis and assessment of posttranslational modifications (PTM) is one of the core competencies of GlycoThera that has been carried out numerous times already for a large number of clients.
Typically, the following parameters are assessed by GlycoThera:

Sialylation / charge profiling of N-glycans (quantitative in mol %)

Quantification and detection of
  • sialylated N-glycans with 1 - 5 and higher sialic acid residues
  • phosphorylated and sulphated glycan structures
  • hybrid-type N-glycans
  • oligomannosidic Man5-9GlcNAc2 glycan chains (neutral and phosphorylated)
  • neutral glycan forms

Antennarity profiling of N-glycans (quantitative in mol %)

Quantification and detection of
  • di-, tri- and tetraantennary glycans with and without N-acetyllactosamine repeats; separation of isomers (e.g. 2,4- and 2,6-triantennary glycans) and isobaric chains (e.g. tetraantennary glycans and triantennary glycans with one LacNAc repeat)
  • N-glycans with and without proximal α1,6-linked fucose
  • type-I (Galβ1-3GlcNAc) and type-II (Galβ1-4GlcNAc) oligosaccharides
  • truncated / incomplete structures (e.g. lacking galactose residues)
  • oligomannosidic Man5-9GlcNAc2 glycan chains (neutral and phosphorylated)
  • Neu5Ac / Neu5Gc content
GlycoThera applies proprietary, GMP-certified HPAEC-PAD mapping techniques and appropriate reference glycan standards; GlycoThera has established a glycan library comprising >200 reference glycan structures analysed by NMR & MS, MS-MS.

Sialic acid content (mol sialic acid / mol glycoprotein)

Quantification and detection of NeuAc and NeuGc in glycoproteins by using GMP-certified HPAEC-PAD

Other PTMs

Quantification and detection of
  • Sulfation
  • Phosphorylation
  • Acylation
  • Glycation
 
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