Stable Protein Gel Storage in Acetonitrile for Mass Spectrometric Analysis

Long-term storage of protein samples for transportation is a challenge in the field of mass spectrometric analysis because the low temperature condition is not easy to be maintained. Here we introduce a simple method to preserve proteins at room temperature for at least one month. In this method, the protein sample is run shortly into a polyacrylamide gel which is then excised after Coomassie staining. The protein gel band is then dehydrated by 100% acetonitrile three times and kept in 100% acetonitrile for storage at room temperature. By the TMT 10-plex based quantitative proteomic analyses, we have found that these proteins are stable in their levels and modifications (phosphorylation, oxidation, and ubiquitination) for 30 days. Further analysis has revealed this storage method also well preserves proteins even at 45 °C. We therefore recommend to use acetonitrile to dehydrate and store protein gel pieces as an effective alternative for sample shipping over days. Therefore, it might facilitate worldwide collaborations in the mass spectrometry-based proteomic research.