Isolation of a novel calcium-binding peptide from wheat germ protein hydrolysates and the prediction for its mechanism of combination

- A novel calcium-binding peptide is purified from wheat germ protein hydrolysate.
- The purified peptide is identified to be Phe-Val-Asp-Val-Thr.
- The possible chelating sites are carboxyl oxygen and amino nitrogen atoms.
- Asp and Thr are mainly involved in formation of chelate.
- The purified peptide is utilized as an ingredient for nutraceutical food.

To isolate a novel peptide with specific calcium-binding capacity, wheat germ protein was hydrolyzed. The hydrolysates were purified using ultrafiltration, anion-exchange chromatography, gel filtration chromatography, and reversed-phase high performance liquid chromatography. The amino acid sequence of the purified peptide was determined and confirmed to be FVDVT (Phe-Val-Asp-Val-Thr). The calcium-binding capacity of FVDVT reached 89.94 ± 0.75%, increased by 86.37% compared to the hydrolysates. The chelating mechanism between FVDVT and calcium was further investigated by Ultraviolet-Visible absorption spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and 1H nuclear magnetic resonances spectroscopy. The results indicated that the oxygen atoms of the carboxy group and the nitrogen atoms of the amido group provided major binding sites. In addition, aspartic acid and threonine show considerable capacity for incorporating with calcium by donating electron pairs. This study provides a feasible approach to isolate calcium-binding peptides and to clarify the possible binding mechanism of calcium and peptide.