Analysis of the multimeric state of proteins by matrix assisted laser desorption/ionization mass spectrometry after cross-linking with glutaraldehyde

We have undertaken a systematic study on the suitability of matrix-assisted laser desorption/ionization mass spectrometry to analyze and determine the multimericity of several proteins after cross-linking with glutaraldehyde. Using both commercially available proteins and: others of viral origin cur rently being characterized in our laboratory, we studied the range of conce ntrations of cross-linker and protein for optimal analysis. Under the condi tions developed during this study, we confirmed the multimeric states of th ree phage PRD1 structural proteins with monomeric masses ranging from 13.5 to 63 kDa. In addition, we addressed the question of the general applicabil ity of the method by using it successfully to confirm the stoichiometry of the heptameric chaperonin GroEL, a bacteria protein with a mass well over 4 50 kDa. Copyright (C) 1999 John Wiley & Sons, Ltd.