|Thannhauser, Theodore - Ted|
Submitted to: Journal of Biomolecular Techniques
Publication Type: Abstract Only
Publication Acceptance Date: 1/25/2008
Publication Date: 2/16/2008
Citation: Yang, X., Thannhauser, T.W. 2008. Getting something for nothing: Regeneration of peptide signals from apparently exhausted MALDI samples by “waterboarding". Journal of Biomolecular Techniques. Vol. 19:52.
Technical Abstract: An often cited advantage of MALDI-MS is the ability to archive and reuse sample plates after the initial analysis is complete. However, experience demonstrates that the peptide ion signals decay rapidly as the number of laser shots becomes large. Thus, the signal level obtainable from an archived sample plate is often too low to be of any practical value upon reuse. Here we report a simple approach that can be used to regenerate peptide ion signals from apparently exhausted MALDI samples by hydration (“waterboarding”). We have found that the average signal obtained from 1, 600 laser shots decayed exponentially over 30 consecutive runs to the point where only 2% remained. After hydration, the signals of the 5 peptides evaluated increased an average of 11 folds compared to their levels before hydration. The benefits of hydration were also confirmed by using tryptic digests of aphid proteins separated by a 2D gel and honey bee royal jelly proteins treated with trypsin in-solution digestion. Hydration of freshly-prepared sample plates did not enhance the signals and generally reduced the signal levels obtainable from virgin samples. Control experiments that involved incubating the exhausted sample plates under vacuum or in sealed chambers under air at atmospheric pressure for various amounts of times did not regenerate the signals. The method presented will find practical use in applications that involve protein discovery using MALDI-MS by allowing for an increase in both the number and confidence of the protein identifications.