How to characterize antibody glycosylation by HILIC-MS

Question: What is N-glycosylation and how do I characterize the N-glycosylation of my antibody? Is it possible to compare batch-to-batch variations?   Answer: Glycosylation is...

Mar 4. 2019 | Thomas Kofoed | 0
1000 proteins quantified in e. coli mock lysate - HCP

Simple way to perform label-free quantification of Host Cell Proteins

Question: I find it difficult to get an accurate label-free quantification of Host Cell Proteins with LC-MS. It also seems that...

Jun 25. 2018 | Ejvind Mørtz | 0

What are ‘Jackpot HCPs’? Do I need a ‘lucky goat’ for precise results in ELISA?

Question: I tested two different HCP ELISA kits on my biopharmaceutical. Why do they give different results and which one is...

May 28. 2018 | Anette Draborg | 0

Quickly compare HCP in different process steps, without an ELISA

Question: I have spent days trying to set up a useful ELISA assay for detecting Host Cell Proteins (HCPs) in my process samples. I'm...

Apr 10. 2018 | Ejvind Mørtz | 0
HPLC analysis of process related impurities by reverse phase mass spectrometry ( LC-MS analysis )

How to identify peaks observed by UV-HPLC in stability studies

Question: We have developed a Reversed-Phase (RP) UV- HPLC chromatography method. It is used for stability studies of our new pharmaceutical protein. How do we...

Jan 24. 2018 | Thomas Kofoed | 0
What is SWATH?

What is SWATH and why is it an advantage for Host Cell Protein analysis?

Host Cell Proteins (HCPs) in protein biopharmaceuticals can be analyzed by mass spectrometry - for both identification and quantification of...

Jun 22. 2017 | Thomas Kofoed | 0

4 reasons why N-terminal sequencing should be done by Edman degradation

Question: How do I obtain the N-terminal sequences of the heavy chain and light chain of my monoclonal antibody?   Answer: mAb N-terminal sequence...

Apr 26. 2017 | Ejvind Mørtz | 0
Protein calculator

GPMAW lite – Protein Molecular Weight Calculator (and much more)

Simple bioinformatics calculations on specific protein sequences When working with proteins you often need to make simple bioinformatics calculations on a specific...

Apr 10. 2017 | Thomas Kofoed | 0
Antibody characterization

Verifying Ile/Leu residues in de-novo sequencing of antibody

Question: I was told that de-novo sequencing by mass spectrometry is not able to distinguish between Ile and Leu residues in my...

Mar 22. 2017 | Fen Yang Reske-Nielsen | 0
Application note - mAb

What purity is required for de-novo sequencing of my antibody?

Question: My monoclonal antibody is not 100% pure, what is the purity required for de-novo sequencing?   Answer: We typically observe two types of protein impurities in...

Mar 20. 2017 | Fen Yang Reske-Nielsen | 0
100% sequence coverage map of antibody

Antibody de-novo Sequencing: How to get 100% sequence coverage

Question: Is it possible to perform a de-novo sequencing of my purified monoclonal antibody without the hybridoma cells?   Answer: Yes! – Your purified antibody can...

Mar 17. 2017 | Fen Yang Reske-Nielsen | 0

Why you need accurate concentration determination of protein standards

How do I quantify my protein standard? Have you ever questioned the quantitative data you get from Bradford, Lowry or BCA protein quantification...

Jan 18. 2017 | Thomas Kofoed | 0
Extinction coefficient protein concentration

Find the Molar Extinction Coefficient of your protein in 3 small steps

Question: I have a purified protein that I would like to quantify accurately in my lab using 280 nm UV measurement...

Nov 15. 2016 | Thanh Ha Nguyen | 0
Analysis method for Mw HCPs (small HCPs) below 20 kDa

Identification of small host cell proteins (low Mw HCPs)

Question: Could you suggest an analysis method to detect low Mw HCPs (small HCPs) below 20 kDa? I work on a drug...

Oct 11. 2016 | Ejvind Mørtz | 0
Amino Acid analysis

4 things to remember about Amino Acid Analysis of proteins & peptides

Amino acid analysis is a method to determine the absolute amounts of individual amino acids in a sample. The method...

Sep 23. 2016 | Ejvind Mørtz | 1
2D PAGE preparation for MALDI ISD

1D SDS PAGE versus 2D PAGE. Any recommendations?

Question: I’m interested in isolating and identifying cell surface receptor proteins. They typically have high Mw, are glycosylated, and also transmembrane...

Sep 18. 2016 | Ejvind Mørtz | 0
Protein scientist at Alphalyse

3 steps to identify & quantify HCP in drug substance homolog to host cell

Question: My HCP antibodies show a reaction towards a drug substance band in my Western blot. Is it possible that it is...

Sep 5. 2016 | Rikke Raaen Lund | 0

How much protein should I load for protein identification by mass spec?

How should I prepare my samples for 2D electrophoresis, and how much protein should I load to get protein ID...

Jun 8. 2016 | Ejvind Mørtz | 0
N- and C-terminal sequencing from PVDF membrane

How to increase protein concentration before loading onto 1D SDS PAGE

Question: I have another question:  Is it ok if I precipitate my samples with TCA prior loading to the SDS-Gel? If not, how...

Jun 7. 2016 | Ejvind Mørtz | 0
Mass spectrometry analysis of protein

Common protein contaminants in mass spectrometric protein ID

Questions: Is the keratin identified by the protein ID service in my 1D gel band a contamination? Or is it...

Jun 3. 2016 | Ejvind Mørtz | 0

Effective 1D/2D PVDF staining protocols (for N-terminal sequencing)

For N-terminal Edman sequencing SDS PAGE you can electro-blot the separated proteins onto PVDF membranes. After PVDF staining you may...

May 24. 2016 | Ejvind Mørtz | 0
Eppendorf tubes with protein

Mass spectrometric identification of proteins from Western blots

Question: Dear Sir, We have an unknown protein recognized in Western blot by autoantibodies that we need to identify. Is it...

May 2. 2016 | Ejvind Mørtz | 0
Preparation of sample for MALDI

What buffer to use for MALDI mass spectrometry analysis of a protein?

Question: What buffer should I use for MALDI Mass Spectrometry analysis of my protein sample? Answer: In general, MALDI-MS is more tolerant...

Apr 28. 2016 | Ejvind Mørtz | 1

Useful Protein Molecular Weight Calculator kDa

Protein molecular weight calculator kDa The rule of thumb for conversion of microgram amounts into picomole amounts at different protein molecular...

Nov 10. 2015 | Ejvind Mørtz | 0

What does the Mascot Score mean?

Question: I just got my protein identification report. What does the Mascot Score mean? Answer: The Protein Identification report contains a list of proteins that have...

Oct 9. 2015 | Ejvind Mørtz | 0

Why is my protein’s N-terminal blocked (and what can I do about it)?

N-terminal sequencing is a requirement according to the ICH Q6B Guideline. This includes structural characterization of recombinant proteins for clinical...

Aug 31. 2015 | Ejvind Mørtz | 2

Protocol for silver staining of gels by mass spec & protein identification

Problems arising from using commercial staining kits: Scientists use silver staining for sensitive detection of proteins separated by 1D and 2D...

Aug 6. 2015 | Ejvind Mørtz | 1

Identification of proteolytic degradation of recombinant protein

Question: I purified a recombinant protein and analyzed it by 1D SDS PAGE. In addition to the intact protein (52...

May 9. 2015 | Ejvind Mørtz | 2

Guide to identification of novel proteins not in public databases

Question: I recently used Alphalyse's protein identification service to analyze my protein. The sample gave me very good MS data. However it...

Dec 2. 2014 | Ejvind Mørtz | 0

Preparing samples for N- and C-terminal sequencing by MALDI ISD?

Question: I am interested in your N and C-terminal sequencing using MALDI ISD. How do I prepare the sample for...

Feb 22. 2014 | Ejvind Mørtz | 0

Assessing stability of protein drug substance & formulated drug product

After protein purification, an important issue is the stability of a protein drug substance and formulated drug product. Stability assays...

Oct 21. 2013 | Ejvind Mørtz | 1

Optimize electroblotting on PVDF membrane for N-terminal Edman sequencing

How do I optimize electroblotting conditions onto PVDF membrane for N-terminal Edman sequencing? Our 12 kDa protein separates well on...

Oct 13. 2013 | Ejvind Mørtz | 0
N- and C-terminal Sequencing

3 Techniques for N- and C-terminal sequencing of proteins

Where does the amino acid sequence start and where does it end? The terminal amino acid sequences are important for the...

Sep 16. 2013 | Ejvind Mørtz | 2

N- and C-terminal protein sequencing using MALDI ISD

Structural characterization of purified natural and recombinant proteins traditionally includes N-terminal Edman sequencing to confirm 5-15 amino acid residues from...

Aug 18. 2013 | Ejvind Mørtz | 0
Order analysis online with quick response

Which databases & organisms are used in mass spec protein ID service?

Question: I would like to identify proteins from an organism where the genome has just been sequenced. How many proteins are...

Nov 16. 2009 | Ejvind Mørtz | 0

Mass Spec for Host Cell Protein monitoring & control in process development

Mass spectrometry based Host Cell Protein identification and quantification Here the Mass Spec Host Cell Protein (HCP) assay is applied for...

Oct 2. 2009 | Ejvind Mørtz | 2
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