Protein Molecular Weight Determination Service

The molecular weight of protein is an important analytical parameter in biochemistry. It is necessary to determine the molecular weight of recombinant proteins and key subunits by a fast and accurate method. Accurate quality determination allows us to assess the correctness of the primary protein sequence, the presence of mutations and post-translational modifications, possible degradation, homogeneity, and the degree of isotope incorporation during labeling.

High-resolution and accurate mass LC-MS and Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) have been widely used in the biopharmaceutical industry. These techniques can provide a wealth of information about protein molecules in each analysis. MALDI-TOF-MS can directly measure molecular weight. ESI-MS high-resolution mass spectrometry analyzes the multi-charge signal obtained by electrospray, and then deconvolutes the signal to obtain accurate molecular weight values. These two methods have their own advantages and applicable fields.

Creative Proteomics is equipped with both of these mass spectrometry systems. Whether you need to confirm the protein spectrum or peptide fingerprint analysis and protein identification of a variety of protein molecular weight analysis, Creative Proteomics can meet your needs to provide customized solutions.

Protein Molecular Weight Determination ServiceFig1. ESI Mass Spectrum of Lac Permease

We Can Provide but Not Limited to:

 ESI-Q TOF-MS Intact Mass Analysis ServiceMALDI-TOF-MS Intact Mass Analysis Service
Salt Impurities ToleranceBetterBad
Sample ConditionLiquidSolid
Protein Mixture IdentificationGoodBad
Combine with LCYesNo
Analysis TimeLongShort
Data InformationMuchLess
Other CharacteristicsIt can also be combined with various quality analyzers.
  • The spatial composition of the sample can be captured.
  • The detection ability of peptides with larger molecular weight, stronger hydrophobicity and lower electric points is stronger.
  • Reanalysis of samples is allowed.

Advantages of Protein Molecular Weight Determination Service:

  • Creative Proteomics provides a comprehensive set of technologies (instruments, columns, databases, methods, etc.) to ensure that every element of a complete protein analysis is reliably determined.
  • The accurate mass analysis of ionization and protein can reach more than 100,000 Da at a low pmol level, with an accuracy of more than 0.1%.
  • For mass spectrometry with a mass accuracy of 5-10 ppm, a more accurate molecular mass measurement can be obtained to distinguish between Asp and Asn, Asn and Leu / Ile, Glu and Gln, Glu and Lys, with only a 1 Da mass difference.
  • Fast turnaround time.
  • We can customize exclusive solutions for you according to your needs and samples.

Sample Requirements

  • Sample status: dry powder, solution
  • Sample size: 10-50ug
  • Sample purity: > 90%
  • During the sample preparation process, try to avoid the use of surfactants, such as SDS, Triton-X, etc. The salt concentration, such as Tris, is also reduced as much as possible.

If you must use a surfactant and a higher salt concentration in the process of preparing the sample, we will first remove the above compounds through relevant experiments after receiving your sample, and then carry out the subsequent molecular weight determination.


  • Nadler W M, Waidelich D, et al. MALDI versus ESI: the impact of the ion source on peptide identification. Journal of proteome research, 2017, 16(3): 1207-1215.

*For Research Use Only. Not for use in the treatment or diagnosis of disease.

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