The low recovery of pertussis toxin (PT) and the low resolving efficiency of chromatography, due to the instability of PT in low salt condition, are the main challenges for its purification. We aplied 2 mol/L urea to prevent the aggregation and disassociation of PT during the purification by ion-exchange chromatography (IEC) and gel filtration chromatography (GFC). The effect of urea on the purification of PT was studied by ELISA assay and non-reduced SDS-PAGE. The activity recoveries of PT and filamentous hemagglutinin (FHA) in IEC and GFC, the resolution efficiency in GFC and the purities of PT and FHA were improved obviously by adding 2 mol/L urea in the mobile phase. The results highlight the potential application of urea in the acellular pertussis vaccine (APV) manufacture procedure.
Adhesins, Bacterial ; isolation & purification ; Chromatography, Ion Exchange ; methods ; Humans ; Pertussis Toxin ; isolation & purification ; Pertussis Vaccine ; chemistry ; isolation & purification ; Solutions ; Urea ; chemistry ; Vaccines, Acellular ; chemistry ; isolation & purification ; Virulence Factors, Bordetella ; isolation & purification

OBJECTIVETo investigate the feasibility of using liquid chromatography (HPLC) to characterize the 3, 4-Dihydroxyphenylalanine (DOPA) redox state of mussel adhesive protein (MAP).

METHODSThe DOPA and protein contents of MAP were determined by HPLC, Arnow and Bradford methods respectively.

RESULTSWith extended oxidation time, the protein contents of MAP samples remained unchanged whereas the DOPA contents declined. The retention times of main peaks in HPLC for both the accelerated oxidation and retained samples shifted as the storage time extended, which could be related to the changes of sample redox state.

CONCLUSIONSThe redox state of MAP can be characterized by the change of HPLC peak retention time. HPLC can be used in the research on the MAP redox state, which is beneficial to the product development and quality control.