Evaluation of different methods of protein extraction and identification of differentially expressed proteins upon ethylene‐induced early‐ripening in banana peels

Abstract

BACKGROUND: Banana peels (Musa spp.) are a good example of a plant tissue where protein extraction is challenging due to the abundance of interfering metabolites. Sample preparation is a critical step in proteomic research and is critical for good results. RESULTS: We sought to evaluate three methods of protein extraction: trichloroacetic acid (TCA)‐acetone precipitation, phenol extraction, and TCA precipitation. We found that a modified phenol extraction protocol was the most optimal method. SDS‐PAGE and two‐dimensional gel electrophoresis (2‐DE) demonstrated good protein separation and distinct spots of high quality protein. Approximately 300 and 550 protein spots were detected on 2‐DE gels at pH values of 3–10 and 4–7, respectively. Several spots were excised from the 2‐DE gels and identified by mass spectrometry. CONCLUSIONS: The protein spots identified were found to be involved in glycolysis, the tricarboxylic acid cycle, and the biosynthesis of ethylene. Several of the identified proteins may play important roles in banana ripening. Copyright © 2012 Society of Chemical Industry