Antibody characterization

Assessing and monitoring the quality of therapeutic mAb products

Question:   I need to ensure the quality and consistency of my mAbs. Which analyses should be conducted?   Answer:   For several years, monoclonal antibodies...

Nov 25. 2019 | Thomas Kofoed |

How to document removal of process-related residual proteins through all purification steps

Question:   My company develops and produces a biologic. Recently, regulatory authorities asked us to document how efficiently downstream purification reduces the...

Sep 25. 2019 | Ejvind Mørtz |
elisa-coverage

Can I use commercial HCP ELISA kits for FDA approval of clinical trial application?

Question:   My company uses a commercial HCP ELISA kit for host cell protein analysis of clinical phase 1 material. We hear...

Jul 10. 2019 | Ejvind Mørtz |

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 |

What are Host Cell Proteins (HCPs)?

Question:   I recently met the term Host Cell Proteins (HCPs) in relation to process development and production of biopharmaceuticals. What are...

Jan 10. 2019 | Ejvind Mørtz |
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 my...

Jun 25. 2018 | Ejvind Mørtz |

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

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 |
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 |
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 |

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 |
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 |
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 |
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 |

Why disulfide bridges are critical quality attributes of biologics

Question:   The activity of my biopharmaceutical protein is low, and I suspect that it is related to decreased protein stability. What...

Mar 7. 2017 | Thomas Kofoed |

Why you need accurate concentration determination of protein standards

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

Jan 18. 2017 | Thomas Kofoed |
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 |
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 |
Amino Acid analysis

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

Why perform Amino Acid Analysis?   Amino acid analysis is a method to determine the absolute amounts of individual amino acids in...

Sep 23. 2016 | Ejvind Mørtz |
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 have transmembrane domains. I’m...

Sep 18. 2016 | Ejvind Mørtz |

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

Question:   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 |
N- and C-terminal sequencing from PVDF membrane

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

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

Jun 7. 2016 | Ejvind Mørtz |
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 |
Eppendorf tubes with protein

Mass spectrometric identification of proteins from Western blots

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

May 2. 2016 | Ejvind Mørtz |
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 to contamination...

Apr 28. 2016 | Ejvind Mørtz |

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 |

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 |

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

Question:   I found that the N-terminal of my protein is blocked. How can I then analyze it by Edman degradation/sequencing?   Answer:   N-terminal sequencing...

Aug 31. 2015 | Ejvind Mørtz |

Protocol for gel silver staining – 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 |

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 kDa),...

May 9. 2015 | Ejvind Mørtz |

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 |

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 analysis?   Answer:   MALDI...

Feb 22. 2014 | Ejvind Mørtz |

Optimize electroblotting on PVDF membrane for N-terminal Edman sequencing

Question:   How do I optimize electroblotting conditions onto PVDF membrane for N-terminal Edman sequencing? Our 12 kDa protein separates well on 1D...

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

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

Question:   Where does the amino acid sequence start and where does it end? Can you describe relevant sequencing techniques?   Answer:   The terminal amino...

Sep 16. 2013 | Ejvind Mørtz |

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 |

Host Cell Protein monitoring & control in process development

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

Oct 2. 2009 | Ejvind Mørtz |
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