Identification of a novel calcium-binding peptide from Lentinula edodes and structure, stability and absorption evaluation of its calcium chelate.

Background: Peptide-Ca chelates are promising calcium supplements. Lentinula edodes (LE) is rich in amino acids with calcium-binding ability, and so it is hypothesized that it can be used to develop peptide-Ca chelates. Additionally, aiming to save time, molecular docking, using Ca or calcium sensing receptor (CaSR) (a regulator of calcium homeostasis) as target, has been applied in the screening of calcium-binding peptides (CBP). In the present study, LE CBP was separated and identified by traditional methods. The optimal CBP was further screened through docking. Then, the structure, stability and calcium absorption of LEVEIHA-Ca were evaluated.

Results: The LE protein hydrolysate was sequentially purified using ultrafiltration followed by anion-exchange chromatography; two subfractions (F33 and F34) of LE CBP were obtained, both of which exhibited higher calcium binding rate. Eight potential CBP in the two subfractions were identified, and leucine-glutamic acid-valine-glutamic acid-histidine-isoleucine-alanine (LEVEHIA), showing the highest affinity with Ca and CaSR, was selected by docking assay. The prepared chelate, LEVEIHA-Ca, formed more compact and larger micelles (1125 ± 2 nm) with lower zeta potential (-20.1 ± 0.3 mv) compared to LEVEHIA. Functional groups including COO-, NH, CN and CO were involved in the chelation between LEVEIHA and Ca. LEVEIHA-Ca was tolerant to high temperature, and most calcium (87 ± 4%) was retained after gastrointestinal digestion. LEVEIHA-Ca exhibited better promoting effects on calcium absorption than casein phosphopeptides-Ca.

Conclusion: LE can be used to prepare peptide-chelate with high calcium absorption. © 2025 Society of Chemical Industry.