KFP‐1, a Novel Calcium‐Binding Peptide Isolated from Kefir, Promotes Calcium Influx Through TRPV6 Channels. Issue 22 (19th October 2021)

• Record Type: Journal Article
• Authors: Chang, Gary Ro‐Lin; Tu, Min‐Yu; Chen, Yu‐Hsuan; Chang, Ku‐Yi; Chen, Chien‐Fu; Lai, Jen‐Chieh; Tung, Yu‐Tang; Chen, Hsiao‐Ling; Fan, Hueng‐Chuen; Chen, Chuan‐Mu
• Is Part Of: Molecular nutrition & food research. Volume 65:Issue 22(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-19
• Subjects: Caco‐2 -- calcium absorption -- calcium‐binding peptide -- kefir -- TRPV6; Food -- Biotechnology -- Periodicals; Food -- Microbiology -- Periodicals; Nutrition -- Periodicals; Food -- Toxicology -- Periodicals; Nutrition -- Periodicals; Food Microbiology -- Periodicals; Food Technology -- Periodicals; Molecular Biology -- Periodicals; 664.0705
• DOI: 10.1002/mnfr.202100182
• Languages: English
• ISSNs: 1613-4125

Abstract

Abstract : Introduction: Kefir is an acidic and alcoholic fermented milk product with multiple health‐promoting benefits. A previous study demonstrated that kefir enhanced calcium absorption in intestinal Caco‐2 cells. In this study, kefir‐fermented peptide‐1 (KFP‐1) is isolated from the kefir peptide fraction, and its function as a calcium‐binding peptide is characterized. Methods and Results: KFP‐1 was identified as a 17‐residue peptide with a sequence identical to that of κ‐casein (residues 138–154) in milk protein. KFP‐1 is demonstrated to promote calcium influx in Caco‐2 and IEC‐6 small intestinal cells in a concentration‐dependent manner. TRPV6, but not L‐type voltage‐gated calcium channels, is associated with the calcium influx induced by KFP‐1. An in vitro calcium binding assay indicates that the full‐length KFP‐1 peptide has a higher calcium‐binding capacity than the two truncated KFP‐1 peptides, KFP‐1∆C5 and KFP‐1C5. Alexa Fluor 594 labeling shows that KFP‐1 is taken up by Caco‐2 cells and interacts with calcium ions and TRPV6 protein. Moreover, KFP‐1 is found moderately resistant to pepsin and pancreatin digestions and enhanced calcium uptake by intestinal enterocytes in vivo. Conclusion: These data suggest that KFP‐1, a novel calcium‐binding peptide, binds extracellular calcium ions and enters Caco‐2 and IEC‐6 cells, and promotes calcium uptake through TRPV6 calcium channels. The present study is of great importance for developing kefir‐derived metal ion‐binding peptides as functional nutraceutical additives. Abstract : Proposed mechanism of action of KFP‐1 for promoting calcium influx in intestinal epithelial cells. Based on the experimental data, it is hypothesized that KFP‐1 increased of intracellular calcium uptake in Caco‐2 cell through TRPV6 calcium channel, but not L‐type VGCC. Therefore, KFP‐1 can transmit dietary calcium from the luminal space of intestinal tract to the circulation system.