Speedy and detailed protein ID of SDS gel bands

Question: The biopharmaceutical company that I work for, consistently uses SDS PAGE and Western Blotting to check protein expression. But this...

Jun 9. 2020 | Thomas Kofoed |
mAb analysis by peptide mapping

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 for proper mAb characterization? Answer: For...

Nov 25. 2019 | Thomas Kofoed |

How to document removal of a process related impurity

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 my 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...

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...

Jun 25. 2018 | Ejvind Mørtz |

How do ‘Jackpot HCPs’ and a ‘Lucky Goat’ influence my 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 |
UV-HPLC data analysis

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

Question:   We have developed a Reversed-Phase (RP) UV-HPLC chromatography data analysis method. It is used for stability studies of our new...

Jan 24. 2018 | Thomas Kofoed |

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 /...

Aug 31. 2017 | Ejvind Mørtz |
What is SWATH?

What is SWATH & why is it an advantage in Host Cell Protein analysis?

Host Cell Proteins (HCPs) in protein biopharmaceuticals can be analyzed by the mass spectrometry SWATH analysis - for both identification...

Jun 22. 2017 | Thomas Kofoed |

4 reasons to perform N-terminal protein sequence analysis by Edman

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

Apr 26. 2017 | Ejvind Mørtz |
Protein molecular weight calculator

GPMAW lite – Protein Sequence Calculator (and much more)

When working with proteins you often need to make simple bioinformatics calculations on a specific protein sequence - and for...

Apr 10. 2017 | Thomas Kofoed |
De-novo sequencing mAb

What purity is required for mAb sequencing by de novo?

Question: My monoclonal antibody is not 100% pure, what is the purity required for mAb sequencing with the de-novo method?   Answer: We typically...

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

How to get 100% antibody sequence coverage

Question: Is it possible to perform a de-novo sequencing of my purified monoclonal antibody without the hybridoma cells? Will I get 100% antibody...

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. Could...

Mar 7. 2017 | Thomas Kofoed |

Why you need accurate concentration determination of protein standards

Question: How do I quantify my protein standard? Is it true that it if it is done incorrectly it can affect...

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

Determine Molar Extinction Coefficient of your protein – 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 (small Mw HCPs)

Question: I work on a drug substance protein with a mass of 15 kDa. I would expect small host cell protein...

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 of proteins is a method to determine the absolute amounts of individual amino...

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 |
Protein N-terminal and C-terminal sequencing of proteins

3 Techniques for protein N- and C-terminal sequencing

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

Sep 16. 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 |
Increase protein concentration on 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 - to increase the protein...

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 identification 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 |

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 kDaThe 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 |

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 |

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 PVDF membrane electroblotting 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 |

Host Cell Protein monitoring in process development – using mass spec

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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