Intact Mass

Weigh in on your protein

Clients come to us to ascertain intact mass not because it’s a complex or onerous task, but because we can link it to a whole lot of other information to give you the best possible overview of the entire protein structure. Also, with our modern mass spectrometers, we achieve a high degree of accuracy.

When we know a protein’s intact mass, or molecular weight, we can achieve insights into important molecular features such as:

• Protein purity, by detecting compounds of different mass
• Post-translational modifications, by evaluating the mass shifts
• Primary structure heterogeneity, by assessing the complexity
• Full-length expression of a recombinant protein, by comparing to the theoretically computed mass

You may wish to determine intact mass to confirm the identity, purity and isoform pattern of a particular protein or peptide. If it’s a glycoprotein you’re investigating, this technique can confirm N- and O-glycosylation variants in a single experiment. Or when combined with a reduction step, we can determine the mass of the protein subunits for you.

In combination with N- and O-deglycosylation analysis, we can also accurately find out the degree of glycosylation.
Determining molecular weight is a key part of ICH Q6B.

Technical information

Intact mass, when combined with other information and the right techniques, can lead to a greater knowledge of a protein’s structure.

We firstly determine the intact mass of a protein by modern MALDI-MS or LC-ESI-MS. After this, you can choose to do the following.

• Obtain the mass extinction coefficient or the protein concentration by mass after amino acid analysis by using MALDI-MS or LC-ESI-MS
• Combine intact mass with N- and C-terminal sequencing by using MALDI-ISD
• Use peptide mapping to allocate the modifications in a protein – which can be detected as a shift in the observed molecular mass – to specific amino acid positions within the protein.

Protein mass can also be determined using 1D SDS-PAGE. At Protagen, we use an especially long separation distance to help deliver a very good estimation of the molecular mass.

Your contact for Intact Mass Determination at Protagen AG

Dr Katja Aschermann Head of Business Development Protein Services. Her team will be happy to assist you with your project. Phone: +49 (0) 231 9742-6300 Email: salesproteinservices@protagen.de