Identification and characterization of a novel calcium-binding peptide isolated from Spirulina platensis via hydroxyapatite affinity.

Spirulina platensis chelating peptide has broad application prospects as a new calcium supplement, yet its structural information remains unclear. A novel calcium-binding peptide was successfully separated and characterized via multispectral techniques and mass spectrometry. The calcium-binding capacity (CBC) of Spirulina platensis peptide purified using hydroxyapatite affinity chromatography (SPH) reached 14.32 ± 1.41 μg/mg, which was associated with the predominance of peptide exhibiting a molecular weight of less than 1 kDa. Moreover, Ca2+ have been demonstrated to promote folding and aggregation of peptide chains by creating coordination bonds with the carboxyl groups of aspartic acid (Asp) and glutamic acid (Glu), thus improving orderliness and structural stability of the peptide backbone. Two potential calcium-binding peptides (SGEDAAE and GEDAAEA) were predicted, and further confirmed that hydrogen bonds and hydrophobic interactions exerted effects in the binding process with the calcium-sensing receptor (CaSR). These results offer substantial support for further developing microalgae peptide-based calcium supplements.