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PTMScan® Motif Antibody Kits
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Immobilized metal affinity chromatography (IMAC) is another strategy for enriching phosphorylated peptides before LC-MS/MS. It uses positively charged ions, commonly Fe3+, to capture negatively charged phosphopeptides.

Comparison of PTMScan® antibody-based and IMAC phosphopeptide enrichment: PTM profiling of human gastric carcinoma (MKN-45) cells.

Phosphopeptides were enriched using various classes of motif/PTM antibodies (tyrosine, proline, serine/threonine, and basophilic), or IMAC methods.

  • Over 20,000 phosphorylation sites were identified across all samples.
  • There was minimal overlap between phosphopeptides enriched using antibody versus IMAC methods.
  • The methods are highly complementary. For optimal coverage of the phosphoproteome use of both antibody-based and IMAC methods is recommended.
Combinations of motif antibodies were used to enrich phosphopeptides

Combinations of motif antibodies were used to enrich phosphopeptides in MKN-45 cells as indicated (A).Area proportional Venn diagram of the overlap between antibody and IMAC enrichment of phosphopeptides from MKN-45 cells. Comparisons were made on unique proteins/sites (B).

View complete dataset showing complementarity of antibody and IMAC enrichment methods.

Please inquire for IMAC services.