BIOC23H3 Lecture : Lec 11 - Mass Spectrometry.doc
Document Summary
Mass spec components: 1) ion source, only positively charged mocs can be analyzed, ionization to produce sample for analysis, types: Maldi: sample mocs (evaporated into gas prior) hit by high. Ions w/ charge, q, accelerated by voltage, u, get the kinetics nrg, qu. Ftms: 3) detector, count # of specific ions, type: Q1 = first mass analyzer = select peptide precursor ion. Collision cell = ions collide with high pressure helium gas resulting in ion fragmentation (breaks down peptide into smaller fragments) Tof = measure masses of resulting fragment ions: sort fragments from smallest to largest and calculate the differences which represents aa. Protein identification: 1) protein extract electrophoresis cut out spot of protein of interest. Digest can apply small peptides to: a) maldi-tov. Multiple peptides use finger-printing database protein: b) tandem mass spec. Apply tandem mass spec to small peptide pieces aa sequence database protein: c) mudpit similar to 2d electrophoresis but doesn"t use electrophoresis at all.