Aug 2026· International Journal of Biological Macromolecules· Vol 379, pp.
153908
· 0 citations· 58 references
Medicine
TL;DR
The results suggest that collagen-derived peptides in silver sillago bone may contribute to calcium retention and transport in this in vitro model, but their specific roles in cellular uptake and relevance in vivo remain to be established.
Abstract
Fish bone-derived calcium may offer an alternative to conventional supplements, but the contribution of specific peptides to calcium bioavailability has not been clearly defined. This study aimed to valorize an underutilized silver sillago bone by identifying novel calcium-binding peptides using de novo LC-MS/MS, molecular dynamic simulation, and Caco-2 monolayer transport assay. Bio‑calcium from silver sillago was prepared through enzymatic hydrolysis, defatting, bleaching, and grinding, then characterized by X-ray diffraction and FTIR spectroscopy. Caco-2 monolayer transport was used for the bioavailability assay. Peptides released after simulated gastrointestinal digestion were analyzed using LC-MS/MS, and calcium-binding potential was assessed through 100 ns molecular dynamics simulations. XRD confirmed the presence of crystalline hydroxyapatite with peaks at 2θ = 26°-32°, while FTIR identified characteristic Amide I-III and phosphate vibration bands. Among the 20 most abundant peptides, we report three novel peptides from silver sillago (SW4, SW16, and SW17) that demonstrated the strongest calcium-binding potential, with Ca2+-peptide distances <0.35 nm, ≥1.2 close Ca2+ ions, and ≥ 25 atomic contacts per frame. SW4 exhibited the shortest mean distance (0.29 nm), highest Ca2+ proximity (1.76 ions), and ~ 28 contacts/frame. In vitro Caco-2 monolayer transport assay showed that bio‑calcium achieved a calcium absorption rate of 28.63 ± 3.88%, comparable to that of calcium carbonate (27.67 ± 3.81%). These results suggest that collagen-derived peptides in silver sillago bone may contribute to calcium retention and transport in this in vitro model, but their specific roles in cellular uptake and relevance in vivo remain to be established.
Phosphorylated salmon bone collagen peptides (P-CP) were developed via hydrolysis and food-grade sodium tripolyphosphate modification, resulting in a peptide-loaded phosphorus content of 334.3 mg/100 g, exhibiting high calcium-chelating capacity (91.21%). Structural analyses (FTIR, XRD, UV-Vis, fluorescence) confirmed phosphorylation and calcium chelation, with conformational changes enhancing mineral binding. Peptide omics analysis revealed that phosphorylation of CP might emphasize involvement of cellular calcium pathway-associated proteins. Proline, serine, and threonine frequently showed up around phosphorylation site within the peptide amino acid sequences. CP phosphorylation offered more calcium chelating site (oxygen in -PO32-) in binding with calcium chelation by ionic interaction. Through in vivo calcium-deficient mice, medium-dose of P-CP-Ca (133.34 Ca mg/kg) superiorly restored serum calcium levels, bone health-associated parameters. This study validates P-CP-Ca as sustainable bone health-improved substances derived from fishery byproducts for functional foods and supplements.
Yuewen Xu, Xuening Yu, Guang Li et al.· Food Chemistry· 0 citations
Across both in vitro and in vivo models, ultra-low molecular weight collagen (LMWCP), with more than 45% di- and tripeptides, exhibited faster early-phase absorption kinetics, thereby enhancing early-phase bioavailability.
Reyhan Nergiz-Unal, Stephan Dierckx, C. Roye et al.· PeerJ· 0 citations
Calcium (Ca), primarily consumed through diet, is essential for skeletal health and various other biological functions in humans. While the mechanisms of Ca absorption are well understood, little is known about the role of food structure properties in Ca release kinetics into the GIT, which may have important implications in Ca uptake. Therefore, the aim of this study was to investigate calcium release kinetics from whey protein matrices with varying structures during gastrointestinal digestion. Whey protein structures (liquid: storage modulus G' = 0.18 Pa at 1 Hz; soft gel: 1791 Pa; hard gel: 4103 Pa) with 8% (w/w) protein and an equal Ca concentration (25 mM CaCl2) were subjected to dynamic in vitro gastric digestion using the Human Gastric Simulator, followed by intestinal digestion of emptied chyme fractions using a static model. Results revealed that the release of both soluble and ionic Ca from whey protein gels was significantly delayed, compared with their liquid counterpart. Slower Ca release patterns from protein gels in the gastric phase led to the release of a higher soluble Ca content in the intestinal phase, especially at early stages of digestion. These findings demonstrated that the physical structure of whey protein gels modulates soluble Ca release rates into the gastrointestinal environment. Further research is required to understand the implications of calcium release modulation in absorption efficiency.
Xinya Wang, Aiqian Ye, Harjinder Singh et al.· Food & Function· 0 citations
Free monomethyl auristatin E (MMAE) released from trastuzumab-valine-citrulline-p-aminobenzyl carbamate (VC-PABC)-MMAE conjugates was quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after incubation in rat plasma at 37°C for 4 days. A wild-type conjugate prepared by maleimide-thiol interchain cysteine conjugation showed 4% ± 3.5% release (n = 3 for each), whereas a Lys188-selective comparator prepared by click chemistry after lipoic acid ligase A-mediated modification showed 4% ± 3.5% release. To examine whether this difference could be explained by linker-payload exposure, molecular dynamics simulations were performed, and solvent-accessible surface areas (SASA) were calculated for representative wild-type interchain cysteine environments and for the Lys188 conjugate. Mean SASA values for the wild-type models were 1132-1293 Å2, all lower than that of the Lys188 model (1524 Å2). Thus, the more stable comparator exhibited the highest modeled exposure. This mismatch between modeled exposure and observed release argues against a simple exposure-driven cleavage mechanism as the primary explanation for the wild-type behavior. Instead, the results suggest that the observed payload release is influenced by bond chemistry in addition to linker exposure.
This study explored interaction mechanisms between mono-, di-, and triacylglycerols (GMO, GDO, and GTO) and high-amylose corn starch (HACS) at atomic resolution using multiple techniques, including Fourier transform infrared spectroscopy, X-ray diffraction, and solid-state NMR, such as 1H spin-lattice relaxation time (T1) and heteronuclear correlation (HETCOR) to analyze molecular mobility and binding sites. Results showed that GMO and GDO exhibited superior complexation ability with starch compared to GTO and successfully induced the formation of V-type structure. HACS-GMO (2.35 s) and HACS-GDO complexes (2.22 s) showed similar T1 relaxation times, which were different from HACS-GTO (2.01 s) and starch (1.92 s), indicating distinct interaction modes. Furthermore, 1H-13C HETCOR indicated the HACS-GDO complex exhibited the strongest cross-peaks, suggesting stronger intermolecular interactions. The C-2,3,5 of starch may be involved as binding sites for the formation of inclusion complexes with GMO and GDO, whereas the interaction between GTO and starch is relatively weak.
Jin Wang, Ruixi Chen, Yunxiang Ma et al.· Food Chemistry· 0 citations
Synthesis and characterization of improved bioactivity and cytocompatibility of hydroxyapatite (HAP) co‐functionalized with gelatin (G) and the amino acid leucine (L) or tyrosine (T) prepared through a hydrothermal process. Phase‐pure, nano HAP with a crystallite size of 15–18 nm and a minimum size of crystallites was noticed in co‐modified samples (GL: 15.39 nm, GT: 15.48 nm) and was successfully confirmed by x‐ray diffraction (XRD). The successful formation of HAP was confirmed by FTIR spectroscopy to identify the presence of characteristic peaks. Analysis of SEM showed that the cofunctionalized samples (GL, GT) had a uniform, fine, and less‐agglomerated morphology and recapitulated the structure of the natural bone mineral in nanostructure. TGA showed an increase in the organic content of the modified samples, indicating a synergistic increase in the GT composite. The DTA results have proven that the incorporation of organic additives had resulted in the structural modification, thereby enhancing the thermal stability of the samples. In vitro evaluation of cytotoxicity was conducted by using MG‐63 osteoblast‐like cells, and the cytocompatibility was excellent, with cell viability being over 90% in all the concentrations of the T, GT, and GL samples tested.
C. Elavarasi, J. V. Kumar, P. Saravanan et al.· Journal of Polymer Science· 0 citations