Alpha-Chymotrypsin was immobilized to CHO activated commercial magnetic particles via the protein free amino groups. Immobilized protease was used to study the phosphorylation degree of porcine pepsin A, as a model acidic protein and phosphoprotein.
The proteolytic digest obtained using the prepared immobilized alpha-chymotrypsin was separated using RP-HPLC and immobilized metal affinity chromatography (IMAC) with Fe(III) ions prior to MALDI-TOF analysis: the presence of phosphopeptide in porcine pepsin A was shown.