In order to determine the intact mass of proteins and peptides Proteome Factory employs ESI-MS using ion trap and high resolution FTICR mass spectrometry followed by charge state deconvolution.

Usual applications are

  • confirmation of protein integrity (e. g. correct sequence length)
  • evaluation of product heterogenity for biosimiliars,
  • detection of PTMs like phosphorylation or chemical modification
  • indirect sequence validation. 

Optionally proteins can be reduced and/or deglycosylated prior to analysis. As a standard, samples are ultrafiltrated/rebuffered into an MS compatible system and analysed by HPLC-ESI-MS to remove residual buffer components. Only pure, salt-free/detergent-free proteins can be analysed directly. Please consult us when your protein requires detergent to be stable in aqueous solution. 

Please note that standard services are designed for the analysis of proteins with the following items in mind:

  • purified protein is required, i. e. buffer must be defined. Industrial grade protein preparations often contain high amounts of impurities. 
  • protein should not require detergent to be kept in aqueous solution.
  • high or especially complex glycosylation will necessitate treatment with PNGase F. Please check this option on the sample submission form or consider glycopeptide analysis. 

Please consult us in case your samples do not meet all requirements to discuss alternative sample preparation or analysis . 


Fig. 1: Mass spectrum of various charge species of intact PNGase F (Elizabethkingia miricola)

Fig. 2: Deconvoluted mass spectrum of intact PNGase F (Elizabethkingia miricola), database mass 34781.59 Da (ave).


Fig. 3: Mass spectrum of various charge species of a Fab-fragment antibody

Price per sample: 

1-2 samples: 500 EUR

3-9 samples: 400 EUR

10 and more samples: 360 EUR

Protein must be soluble in aqueous solution without detergents. Consult us when sample buffer contains detergent.