Protein mixture analysis by mass spectrometry

摘要

Analysis of protein mixtures comprises enzymatic digestion, separation by chromatography and trapping of separate chromatographic fractions. Samples are prepared on a sample carrier together with a matrix substance. The digested peptide samples are ionized by matrix-supported laser desorption in a flight time mass spectrometer where the flight times are measured to establish the masses of the digested peptide ions. Analysis of protein mixtures comprises digesting all the proteins in the mixture with a common digestion enzyme. The digested peptides are separated by chromatography and the separate chromatographic fractions are trapped. Samples are prepared on a sample carrier, using samples from the digested peptide fractions together with a matrix substance. The digested peptide samples are ionized by matrix-supported laser desorption in a flight time mass spectrometer where the flight times are measured to establish the masses of the digested peptide ions. The subsidiary ions are measured from all or selected digested peptide ions using matrix assisted laser desorption ionization (MALDI) tandem flight time mass spectrometry. The proteins are identified through searches of the protein sequences in cDNA or DNA databases.