Proteome analysis and selenium-binding peptide identification on proteins sequentially extracted from loach (Misgurnus anguillicaudatus)

Abstract

Loach (Misgurnus anguillicaudatus) is known as a selenium-rich aquatic product. In present study, a sequential extraction method was applied for separation of water, salt and alkali-soluble proteins from loach (Misgurnus anguillicaudatus). The extracted proteins (included 12 water-soluble, 4 salt-soluble and 7 alkali-soluble proteins) were subjected to molecular weight analysis by SDS-PAGE and MALDI-TOF MS. Then, water soluble proteins were chosen for further ion exchange purification after selenium tracking by ICP-MS. The selenium containing peptides in water soluble proteins were identified by ESI-MS. Four proteins including creatine kinase, cytochrome P450 aromatase, beta-actin and glyceraldehyde 3-phosphate dehydrogenase were identified. Among these proteins, two selenium-containing peptides from beta-actin and cytochrome P450 aromatase were identified. The results of proteome analysis provide valuable molecular information of loach proteins. Moreover, it helps to understand the effect of selenium on redox systems in loach and its antioxidant functions.