Binding mechanism, digestive stability, and cellular interactions of a potential organic Iron supplement: Fermented scallop skirt peptide (DDDHPGIF)-Iron complex.

The fermentation-derived scallop skirt peptide (DDDHPGIF) with strong ferrous ion-binding capability (95.17 ± 0.30 %) was identified in our previous study. However, the structure-function relationship of the peptide prepared by fermentation was still unclear. This study elucidated the binding mechanism, digestive characteristics and transport modes of the fermentation-derived peptide. We hypothesized that the binding process involved the formation of coordination bonds between the carboxyl groups and ferrous ions, followed by self-assembly through intermolecular hydrogen bonds, resulting in a stable and uniform complex. Furthermore, DDDHPGIF and its ferrous chelate (DDDHPGIF-Fe) had excellent digestion stability, with retention rates of 95.09 % and 93.08 %, respectively. The retention rate was the highest of the available reports, showing the unique advantages of the peptide sequence. Finally, we inferred the transport mechanisms of DDDHPGIF and DDDHPGIF-Fe included active transport and endocytosis. This study provides a theoretical basis for developing ferrous chelating peptides from aquatic by-products using microbial methods.