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Protein Phosphorylation

Resin Elution Selectivity

Product No: P 9740

Resin Elution Selectivity - MALDI-MS

Figure 2. MALDI mass spectra of A) Crude ß-casein tryptic digest (113 pmol/µL) prior to loading on the PHOS-Select Resin and B)-E) purified phosphopeptides after elution from the PHOS-Select Resin under various elution conditions. Eluents were as follows: B) 0.15 M NH4OH, C) 0.4 M NH4OH, neutralized with formic acid prior to analysis, D) 0.15 M NH4OH, 25% ACN, and E) 5% formic acid, 25% ACN.

Binding Capacity Study
Species Molecular
Weight (Da)
phosphate (MUP)
256.14 0.9 4.5
2061.96 0.5 8.0
3122.92 1.0 5.5
Binding capacities for the two formats were determined using purified phosphorylated molecules. Binding of MUP was determined via a fluorescence assay. Binding of the mono and tetraphosphopeptides was determined using HPLC-MS analysis.