Diagonal gel electrophoretic analysis of protein disulfides: Principles and applications

Protein cysteine residues are constantly undergoing redox modifications, and many of them are involved in disulfide formation. In this chapter, we first give an overview of the diagonal gel analysis method for the identification of protein disulfides followed by the application of the method for the identification of mitochondrial proteins that have endogenous disulfide bonds or form disulfide bonds upon oxidative stress. Data that show that the albumin precursor protein could be identified by this method, and that many proteins form disulfide bonds after treatment with diamide are presented. The data presented in this chapter indicate that this diagonal gel analytical method, when used in conjunction with mass spectrometric peptide sequencing, can provide a powerful tool for studying protein disulfide proteomics.