Purification of an iron-chelating peptide from spirulina protein hydrolysates

Abstract

Iron-chelating peptide was purified from spirulina protein hydrolysates. Spirulina protein was hydrolyzed using Alcalase and Flavourzyme, and the degree of hydrolysis was determined using a trinitrobenzene sulfonic acid assay and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The spirulina protein hydrolysates were ultra-filtered to isolate the components below 3 kDa, which were then fractionated by Q-Sepharose fast flow and Sephadex G-15 columns. The iron-chelating activity of each fraction was determined, and the peptide with the highest activity was isolated and identified by matrix-assisted laser desorption/ionization-time of flight/time of flight mass spectrometry. Amino acid sequence of the iron-chelating peptide was identified to be Thr-Asp-Pro-Ile(Leu)-Ala-Ala-Cys-Ile(Leu), which has a molecular weight of 802 Da. Moreover, due to its ability to chelate iron, the isolated peptide could be used as an iron supplement.