ISSN:
1573-904X
Keywords:
protein mapping
;
mass spectrometry
;
methionine oxidation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Purpose. To isolate and characterize a monomethioninesulfoxide variant of the commercially available therapeutic protein interferon α-2b. Methods. The methionine (Met)-oxidized variant was isolated by reverse-phase high performance liquid chromatography and characterized by SDS-PAGE, peptide mapping and mass spectrometric analysis of the trypsin/V8-generated peptide fragments. The biological and immunological activities of the isolated variant were also evaluated. Results. The rHuIFN α-2b variant was found to contain a Met sulfoxide residue at position 111 of the rHuIFN α-2b molecule. The far-UV CD spectra showed a slight loss of α-helical content and an increase in the β-sheet contribution. The CD spectra indicate that both chromatographic conditions and Met oxidation contribute to the observed secondary structure changes. Both interferon α-2b main component and its methionine-oxidized variant showed different reactivity to monoclonal antibodies employed in immunoassays for the protein. Conclusions. A monomethioninesulfoxide rHuIFN α-2b variant was found to be present in the rHuIFN α-2b bulk drug substance in solution. The Met111 residue was identified as Met sulfoxide by comparative tryptic/V8 mapping and mass spectrometric analysis. Nevertheless, the oxidation of the Met111 residue did not seem to have a detectable effect on the biological activity of the molecule.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1016059902645
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