Purification and characterisation of a zinc-binding peptide from oyster protein hydrolysate

Abstract

A novel zinc-binding peptide produced from oyster protein hydrolysis using pepsin was purified and characterised. The hydrolysate was fractionated by immobilised metal ion affinity chromatography (IMAC-Zn2+). The zinc-binding peptide identified by reverse-phase high-pressure liquid chromatography (RP-HPLC) and sequenced by liquid chromatography (LC/LTQ) mass spectrometry (sequence from N to C terminal) had a molecular weight of 1882.0 Da. The zinc-binding capacity of the peptide (HLRQEEKEEVTVGSLK) was 6.56 μg mg−1 and it was preserved at 85.98% of its original level upon in vitro simulated digestion. The UV–vis and FTIR spectra demonstrate that the amino nitrogen atoms and the oxygen atoms belonging to the carboxylate groups are the primary binding sites for Zn2+. The results provide a feasible approach to isolate zinc-binding peptides and contribute to clarification of binding mechanism between zinc and peptides.

Keywords

• Zinc-binding peptide
• Oyster protein
• Hydrolysates
• Immobilised metal affinity chromatography