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...
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...
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...
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...
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...
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...
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 /...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...