Purification and identification of adipogenic-differentiating peptides from egg white hydrolysate

Egg proteins are a good source of bioactive peptides. Previous work from our research group has demonstrated the potential of egg white hydrolysate (EWH) for enhancing adipogenic differentiation and insulin signalling in 3T3-F442A pre-adipocytes. EWH was prepared by a combination of thermolysin and pepsin. Here, in this study, we aimed to identify the responsible peptide(s) in EWH. EWH was fractionated stepwise by ultrafiltration, C18 Sep-Pack cartridge, cation-exchange chromatography, and reverse-phase chromatography. The two most active fractions were analyzed by LC-MS/MS and 42 peptides were identified. Eleven peptides were synthesized and WEKAFKDED, QAMPFRVTEQE, ERYPIL, and VFKGL from ovalbumin were validated with peroxisome proliferator-associated receptor gamma stimulatory activity in adipocytes. For the first time, adipogenic differentiating peptides were characterized from egg white proteins. This data is pivotal for future structure-function studies of adipogenic peptides.