Internal Sequencing Samples (back to top)
For samples from organisms whose genomes are sequenced, mass mapping is certainly the method of choice for protein identification.  Alternatively, we offer internal sequencing for protein primary structure characterization in order to assist in the cloning of proteins from organisms whose genomes are not fully sequenced.  Please be advised that, in general, internal sequencing is significantly more costly and time-consuming than any of our other analytical methods.
Samples for internal sequencing are most conveniently submitted in an SDS-PAGE gel, just as in mass mapping analysis.  (Please consult Dick Winant prior to submitting any sample not contained in a gel.)  However, the protein must be in much higher abundance for internal sequencing.  We recommend 100 pmol for best results.
Please place your order through our online ordering system.

Protein Sequencing Requirements For All Samples (back to top)
Ideally, samples should contain pure protein. This is crucial for the success of the analysis and for the proper maintenance of our equipment.
Best is to electroblot your sample onto PVDF membrane.  Blotted samples should contain at least 20 pmol of protein.  More is always better.  If you intend to submit a sample in solution please discuss the project with Dick Winant first.
Please let us know the protein’s molecular weight and species of origin.  Also, it is extremely helpful if you let us know the source of possible contaminating proteins.  For example, if your sample may contain IgG or tissue culture constituents or if the sample has been obtained from a recombinant host, we would like to know this sort of thing in advance.
Please place your order through our online ordering system.

Mass Mapping Samples (back to top)
Mass mapping is usually performed on protein bands purified by electrophoresis on SDS-PAGE gels. (The method is equally applicable to proteins in solution.  However, please consult Dick Winant prior to submitting any sample not contained in a gel.)
Any gel spot that can be visualized by Coomassie staining is an excellent candidate for mass mapping, as are silver stained spots of moderate intensity.  If gels are to be silver stained, one must avoid glutaraldehyde as a fixative agent.  Several commercial silver stain kits are available and are generally identified as “mass spec compatible”.

The gel should be protected from contamination by human hands and from dust in the air. Keratins contained in dust are a common form of contamination and their presence must be minimized by the use of clean glassware, reagents, etc.  Most importantly, submit your samples in nuclease-free Eppendorf tubes.  It is best to also submit a blank region of gel along with the sample to serve as a control.  There is no charge for analysis of the blank.
Please place your order through our online ordering system.