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