1P-33 PDF
MALDI MS analysis of most sensitive backbone amide region of protein in solution
The flexibility of an equine myoglobin has been examined from the standpoints of the accessibility of acid (proton or hydronium ion H3O+) in hydrolysis and of active hydrogens of matrix molecule in matrix-assisted laser desorption/ionization in-source decay (MALDI-ISD) to the backbone amide region. The acid hydrolysis and MALDI-ISD result in the cleavage of C-N bond and N-Cα bond on the backbone, respectively, by which hydronium ion and hydrogen atom attack on the backbone carbonyl oxygens. The results obtained will be discussed on the basis of the flexible amino acid residues reported so far from X-ray crystallography and NMR, and also we examined secondary structure contents and conformations of analyte protein by using circular dichroism (CD) spectra.