Attention:

Certain features of Sigma-Aldrich.com will be down for maintenance the evening of Friday August 18th starting at 8:00 pm CDT until Saturday August 19th at 12:01 pm CDT.   Please note that you still have telephone and email access to our local offices. We apologize for any inconvenience.

Protein Identification

Proteins carry out the work in plant cells. One gene can code for multiple proteins; many proteins undergo post-translational modifications. Thus only direct identification of the total complement of proteins in an extract gives a true picture of the functioning units under different conditions or in different plant species. We offer proteomic grade endoproteinases for digestion of protein spots from 1- or 2-D gels. The resultant peptides can be sequenced by mass spectrometry, or in some cases by Edman degradation in a sequencer. In many cases tryptic peptides are sufficient for identifying a protein and its modifications. A particular protein may, for example, be phosphorylated in meristematic tissue, but not in roots. We also offer a set of kits to calibrate MALDI mass spectrometry instruments