Preparation, isolation and identification of iron-chelating peptides derived from Alaska pollock skin

• Alaska pollock skin could be utilized to generate iron-chelating peptides.
• Low molecular weight (below 500 Da) hydrolysate derived from Alaska pollock skin exhibited high chelating activity.
• Ser-Cys-His (MW: 345 Da) was identified as an iron chelating peptide.
• Chelating activity of Ser-Cys-His should attribute to both its low molecular mass and amino acid composition.

Alaska pollock skin as aquatic by-product was usually discarded in food processing. Iron deficiency has been a nutritional problem for a long period. In this study, Alaska pollock skin was used to generate iron-chelating peptides after being treated by commercial enzymes. Sequential chromatography, including immobilized metal affinity chromatography (IMAC) and reversed phase high performance liquid chromatography (RP-HPLC), was used for capturing and purifying iron-chelating peptides. One tripeptide, with high iron-chelating activity, was obtained and identified by electrospray ionization tandem mass spectrometry (LC–ESI-MS/MS). The amino acid sequence of the iron-chelating peptide was identified to be Ser-Cys-His (MW: 345 Da). These results show that Alaska pollock skin could be utilized to generate iron-chelating peptides as an iron supplement in functional food industry.