The Protein Man's Blog | A Discussion of Protein Research

Protein crosslinking reagents or crosslinkers can be accurately defined as molecules containing two or more reactive ends that are capable of chemically attaching to specific functional groups on proteins or other molecules. These reagents are generally used in creating detectable scientific probes to facilitate a number of proteomics methods, including Western blotting, ELISA and other strategies for studying protein-protein interactions.

Most biological samples contain non-protein substances and/or contaminants that may interfere with the resolution of the electrophoretic separation. Considering the fact that cell lysates usually contain macromolecules and small ionic molecules which may interfere with the electrophoretic process, these agents should be eliminated prior to electrophoresis, especially if their amount exceeds the critical interference threshold.

There is simply no other way around it. You need to break down the walls (the cell wall, that is) to extract the good stuff. While you can easily accomplish this task when extracting proteins from mammalian cells (they have no cell walls to begin with), it can be more difficult when you are working with plants, yeast, bacteria, fungi and Archaea. These organisms have rigid cell walls that protect the basic cell structure against destructive mechanical forces.

Basically, protein tags are peptide sequences that are attached to proteins to facilitate easy detection and purification of expressed proteins. In addition, they can also be used to identify potential binding partners for your protein of interest.