Peptide mass mapping sample preparation

Matrix mixtures have also been used for improved MALDI-MS performance for both proteins and peptides. For example, a mixture of DHB and HCCA was found to improve spot-to-spot reproducibility for peptide mass mapping and to increase the protein sequence coverage [20]. For examples of other matrices useful for peptide analysis, see Table 3.2. Membrane proteins can be efScientiy analyzed using optimized sample preparation methods and detergents, as described by Cadene and Chait [22]. Also, in situ liquid-liquid extraction using ethyl acetate and HCCA may enable the analysis of integral membrane proteins by MALDI-MS [23]. For additional information on the choice of matrix and sample preparation, see also Chapter 1, Section 1.8. 

The introduction of delayed ion extraction in MALDI-TOF instruments in 1995 resulted in a tremendous improvement in analytical performance, mass resolution and accuracy. Using this technique, peptide mass mapping gained high specificity for protein identification and an ability to identify individual components among simple protein mixtures [60, 61]. Improved sample preparation methods also provided an enhanced sensitivity to enable analysis of femtomolar levels of protein [5, 19], Today, the automation of MALDI-MS data acquisition enables the analysis of hundreds of samples each day in large-scale protein identification experiments [62]. 

Jensen, O. N. 1999. Sample preparation methods for mass spectrometric peptide mapping directly from 2-DE gels. In 2-D Proteome Analysis Protocols, Link, A. I, ed., Humana Press (Totowa, New Jersey), 513-530. 

Jensen, O.N. Wilm, M Shevchenko, A. Mann, M. Sample Preparation Methods for Mass Spectrometric Peptide Mapping Directly From 2-DE Gels. Methods Mol. Biol. 1999,112,513-530. 

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