Peptide mapping of recombinant human interferon-gamma by reversed-phase liquid chromatography with on-line identification by thermospray mass spectrometry and UV absorption spectrometry.

The detection and identification of minor peaks in a complex peptide map of recombinant human interferon-gamma was realized by on-line analysis of the eluted peptides using thermospray mass spectrometry and UV absorbance spectrometry. By this procedure the time-consuming process of collection, purification and chemical sequence analysis is avoided. Owing to the formation of multiple charged ions, the domain of the covered masses is extended. Fragmentation of the peptides in the thermospray source was observed resulting from, amongst others, cleavage by acid hydrolysis of peptide bonds involving an aspartic acid. This was of great use for the identification of peptides in a digest of recombinant human interferon-gamma by Staphylococcus aureus strain V8 endoprotease.