Separation of Iron-Binding Peptides from Shrimp Processing By-products Hydrolysates

Separation of iron-binding peptides derived from shrimp processing by-products (SPB) by Alacase hydrolysis was investigated. The highest iron-binding capacity of the hydrolysate (17.5 μmol/g of protein) was obtained with Alacase at a degree of hydrolysis of 8%. The molecular weight (MW) distribution on gel permeation chromatography (GPC) showed that it was ranging from 1 to 6 kDa. By separating with ion-exchange chromatography on SP-Sepharose Fast Flow and gel filtration on Sephadex G-25, one fraction with highest iron-binding capacity of 8,800 μmol/g of protein was purified, and the purification fold of 502 was obtained. When the highest iron-binding capacity fraction was applied on RP-HPLC column, there were four main peaks. By comparing with the infrared spectra of the iron-binding peptides and iron-peptides complex, it was suggested that the principal site of iron-binding corresponded primarily to the carboxylate groups and to a lesser extent to the peptide bonds.