Search Results (311)

The life-threatening disease pertussis, also known as whooping cough, is caused by a complex interplay of several virulence factors produced by the bacterium Bordetella (B.) pertussis. These include the AB-type protein toxin pertussis toxin (PT), the main causative agent of pertussis. After infection with B. pertussis, PT is released and binds to its human target cells, which internalize PT. The enzyme subunit of PT is then taken up into the cytosol, where it catalyzes the ADP-ribosylation of the α-subunit of inhibitory GTP-binding proteins from the Gαi type. This ultimately leads to the development of the characteristic clinical symptoms associated with pertussis. Pertussis is a vaccine-preventable but highly infectious respiratory disease, and especially younger children are prone to develop severe pertussis. Despite the vaccination, over the past few years, increasing case numbers have been reported globally. Moreover, treatment options are strongly limited to antibiotics and symptomatic treatment. Therefore, novel therapies against toxin-mediated diseases are urgently required, while AB-type toxins such as PT are promising pharmacological targets to combat these associated diseases. To identify novel pharmacological inhibitors for AB-type toxins, huge potential lies within the human proteome/peptidome. Endogenous protein or peptide inhibitors for bacterial toxins might have evolved as part of the innate immunity and are awaited to be discovered. The scientific community is committed to identify potential candidates through targeted screening or explorative hypothesis-driven approaches. This review summarizes the recent efforts in the identification and characterization of the human body’s own proteins and peptides that inhibit PT. PT-inhibiting peptides were found by unbiased screening of peptide libraries from human hemofiltrate or hypothesis-driven evaluation, and PT-neutralizing mechanisms were discovered in cell-based approaches. The identification of endogenous peptides and proteins, e.g., defensins and α₁-antitrypsin, as potent inhibitors of PT paves the way towards the development of novel therapeutic options against pertussis. Full article

Pancreatic lipase (PL) plays a central role in dietary lipid digestion and is a promising target for food-derived inhibitors. In this study, pea protein hydrolysates (PPHs) with PL inhibitory activity were prepared by enzymatic hydrolysis and characterized for their functional and peptidomic properties. Compared with pea protein isolate, PPH showed lower surface hydrophobicity, and moderate antioxidant activity. Peptidomic analysis identified 1740 peptides in the active hydrolysate. Combined in silico screening and in vitro validation further identified three peptides, GFSL, WFE, and FGF, as effective PL inhibitors, with IC₅₀ values of 337.81 ± 17.32, 473.32 ± 19.61, and 689.45 ± 39.32 μM, respectively. Molecular simulations indicated that these peptides interact with the catalytic pocket of PL mainly through hydrophobic interactions, van der Waals forces, and hydrogen bonding, with Ile79 serving as a key residue for peptide recognition. Overall, these findings indicate the potential of pea-derived peptides as natural PL inhibitors and support their application as functional food ingredients for modulating lipid digestion. Full article

Marine-derived bioactive peptides have attracted increasing attention as value-added functional ingredients. In this study, peptides (<3 kDa) were prepared from yellowfin tuna processing by-products and further fractionated by Sephadex G-25 gel filtration. The major fraction (TBP-MF) exhibited markedly improved compositional homogeneity compared with the unfractionated hydrolysate (TBP), providing a well-defined peptide system for subsequent characterization and biological evaluation. Physicochemical analyses demonstrated that TBP-MF possessed enhanced thermal stability and a more ordered secondary structure, characterized by pronounced β-sheet enrichment, as revealed by TGA/DSC, FTIR, and circular dichroism analyses. Morphological and colloidal characterization further showed that TBP-MF formed relatively uniform lamellar and fibrous assemblies with a narrower particle size distribution and reduced electrostatic stabilization, indicating a higher tendency toward ordered self-association. Peptidomic profiling combined with in silico analysis revealed that TBP-MF was enriched in short peptides with relatively higher PeptideRanker scores and a functional motif distribution containing relatively more neuro-related annotations, although angiotensin-converting enzyme (ACE)- and dipeptidyl peptidase IV (DPP-IV)-related motifs remained predominant in both groups. In differentiated PC12 cells, TBP-MF exhibited excellent cytocompatibility and induced a stable, concentration-dependent increase in the Cell Counting Kit-8 (CCK-8) readout (OD₄₅₀), indicating enhanced cellular metabolic activity and/or increased cell number. In addition, TBP-MF significantly increased intracellular levels of key neurochemical factors associated with sleep-related regulation, including tetrahydrobiopterin (BH4), serotonin (5-HT), and γ-aminobutyric acid (GABA). Overall, this study highlights yellowfin tuna by-products as a promising marine resource for bioactive peptides and suggests that fractionation-driven structural refinement is associated with neuro-related biological activity in differentiated PC12 cells. These findings support the potential application of marine by-product-derived peptides as functional ingredients in health-related fields. Full article

Organic farming is increasingly promoted as a sustainable alternative to conventional wheat production; however, its effects on grain quality and immunogenic potential remain insufficiently understood. This study evaluated the influence of the farming system (organic vs. conventional) on grain composition, technological quality traits, immunochemical reactivity, and immunogenic peptide profiles in 13 durum wheat varieties, including traditional and modern Tunisian varieties. Protein fraction content, amino acid composition, gluten-quality parameters, starch content, and immunochemical reactivity against anti-gliadin antibodies were determined. In addition, in vitro digestion followed by LC–MS/MS peptidomic analysis and epitope mapping was performed on representative ancient and modern varieties to investigate the release of celiac-disease-related immunogenic peptides after simulated gastrointestinal digestion. Protein content and quality traits were mainly genotype-dependent, with no consistent effect from the farming system across all varieties. Organic farming was associated with reduced starch accumulation (3.2–39.9% reduction) and lower immunochemical reactivity. Peptidomic analysis further revealed a reduced number and relative abundance (20.8–43.6% lower abundance) of immunogenic peptides in organically cultivated wheat compared with conventionally grown counterparts. This study highlights the significant interaction between the genotype and farming system, and provides a novel demonstration that organic management can reduce the abundance of celiac-disease-related immunogenic peptides, particularly in ancient varieties. Full article

Neuropeptides regulate diverse physiological and behavioural processes in parasites, yet their functional roles in the infective larval stages of Schistosoma mansoni remain poorly defined. In this study, we identified miracidia-derived putative neuropeptides and examined their roles in regulating miracidial behaviour. Peptidomic analysis revealed ten putative neuropeptides, including five whose proteomic identification in this life stage was previously unreported. Neuropeptide precursor proteins were evaluated for stage-specific expression and Schistosoma genus specificity to prioritise candidates with potential functional and biocontrol relevance. Protein–protein interaction analysis identified Smp_176700 as a highly connected neuropeptide precursor associated with proteins implicated in miracidial structure and infection. Eight putative neuropeptides derived from six precursor proteins were synthesised and externally applied to miracidia in acute (1 min) and prolonged (360 min) behavioural assays. During acute exposure, most peptides induced significant concentration-dependent behavioural changes at 3 mg/mL and 0.1 mg/mL, characterised by reduced swimming velocity and increased directional change, with no significant effects at 0.01 mg/mL. Prolonged exposure revealed peptide-specific effects, with ASLSYF-OH and FLLGLPPSLRQH-OH producing the most pronounced behavioural modulation. These findings demonstrate that S. mansoni miracidia express bioactive neuropeptides capable of modulating larval behaviour, providing insight into schistosome neurobiology and identifying potential targets for transmission-blocking interventions. Full article

Background/Objectives: Ejiao, a macromolecular protein complex derived from donkey hide, is a traditional Chinese medicine with clinically demonstrated efficacy against ulcerative colitis (UC). Due to its large molecular size and poor absorbability, its therapeutic effects are presumed to depend on gut microbiota. We hypothesized that specific gut bacteria capable of degrading Ejiao might also mediate its biological functions. Methods: To test this hypothesis, a systematic investigation was conducted by integrating culturomics, proteomics, metabolomics, 16S rRNA gene amplicon high-throughput sequencing, and animal disease models. Results: A total of 134 human gut bacterial strains capable of utilizing Ejiao as a nutrient source were isolated. Among them, Ligilactobacillus salivarius D3-8 exhibited the strongest growth in Ejiao-based medium. Genomic analysis identified 63 protease/peptidase genes, and peptidomic profiling confirmed its degradation activity, which released 50 novel peptides. Notably, administration of L. salivarius D3-8 alone significantly alleviated dextran sodium sulfate (DSS)-induced colitis, concurrently increasing the abundance of beneficial bacterium Dubosiella newyorkensis and elevating the anti-inflammatory metabolite indole-3-carbinol via upregulated tryptophan metabolism. Conclusions: Our findings identify L. salivarius D3-8 as both a dedicated Ejiao-degrader and a protective probiotic against colitis. This work provides direct evidence that gut bacteria can utilize Ejiao and proposes a potential novel mechanistic framework in which the biological effects of Ejiao may be mediated through its interaction with specific, functionally potent degraders such as L. salivarius D3-8. Full article

Comparative studies report inconsistent peptide yields, bioactivities, and sensory outcomes for Alcalase across substrates, creating uncertainty about when it should be favored over other proteases. This study mapped research on hydrolysis of food proteins with Alcalase to quantify scientific output, organize thematic trends, and identify gaps relevant to peptide-based functional foods. A bibliometric analysis of Web of Science records (2004–2024) was performed in R (bibliometrix), using co-occurrence networks, temporal overlays, and conceptual mapping. The dataset comprised 203 documents from 78 sources, exhibiting a 10.3% annual growth rate and a 36.9% international co-authorship rate. Themes clustered around antioxidant and angiotensin-converting enzyme (ACE) inhibitory peptides, particularly in dairy and marine matrices, are supported by workflows combining Alcalase hydrolysis with size-guided ultrafiltration, RP-HPLC (Reverse Phase High-Performance Liquid Chromatography), and, more recently, in silico analyses and encapsulation studies. Recurrent limitations were identified: heterogeneous hydrolysates and uneven reporting that hinder sequence–activity correlations, gastrointestinal degradation and bitterness affecting applicability, and scale-up and purification choices influencing feasibility. The mapping clarified where Alcalase enables bioactive peptide generation and highlighted practical priorities, including protocol standardization and enzyme benchmarking, the integration of peptidomics and machine learning with targeted assays, and formulation-focused validation (encapsulation, stability, and delivery) to bridge in vitro activity to real-world use. These directions support the production of reproducible, application-ready peptide ingredients. Full article

Background/Objectives: Collagen hydrolysates are widely used as nutritional ingredients for skin and joint health; however, growing evidence indicates that collagen may also exert beneficial effects on cardiometabolic pathways. Short peptides have been shown to modulate angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV), key regulators of blood pressure and glucose homeostasis. This study aimed to assess the dual ACE- and DPP-IV inhibitory and GLP-1 stimulation activities, respectively of a tripeptide-enriched formulation (CH). The study was performed using a benchmark collagen hydrolysate (BCH) as reference. Methods: ACE and DPP-IV inhibitory activities were evaluated using in vitro enzymatic assays. Cellular compatibility and in situ DPP-IV inhibition were assessed in Caco-2 intestinal cells, while glucagon-like peptide-1 (GLP-1) secretion was measured in STC-1 enteroendocrine cells. The degree of hydrolysis was determined by OPA assay, and nanoLC–HRMS was used to characterize and compare the proteomic profiles of the samples. Results: Both hydrolysates exhibited dose-dependent ACE and DPP-IV inhibition; however, CH showed significantly higher inhibitory activity at comparable concentrations. CH also reduced cellular DPP-IV activity in Caco-2 cells and stimulated GLP-1 secretion in STC-1 cells, whereas BCH showed limited or non-significant cellular effects. Peptidomic analysis revealed an enrichment of short- and medium-length peptides in CH, while BCH contained a higher proportion of long peptides (>2000 Da). Consistently, CH exhibited a 1.7-fold higher degree of hydrolysis than BCH. Conclusions: The tripeptide-enriched collagen hydrolysate demonstrated superior enzymatic and cellular bioactivity compared with the benchmark formulation, supporting its potential as a multifunctional bioactive ingredient for health applications. Full article

Peony seed meal (PSM), a protein-rich by-product of oil extraction from Paeonia ostii, represents an underutilized resource with significant potential for functional ingredient development. In this study, an integrated strategy combining artificial neural network (ANN)-guided hydrolysis, peptidomics, molecular simulation, and cellular validation was employed to identify antioxidant peptides from PSM. Neutrase was selected as the optimal protease, and hydrolysis conditions were optimized using a backpropagation ANN model (R = 0.9935), yielding a hydrolysate with strong radical-scavenging activity (DPPH^• IC₅₀ = 0.30 mg/mL; ABTS^•+ IC₅₀ = 0.07 mg/mL). LC–MS/MS identified 364 peptides, predominantly low-molecular-weight sequences. In silico screening highlighted four candidates (FRF, WQFR, FEFR, and RWL) with favorable binding toward ABTS^•+, DPPH^•, and Keap1. Molecular docking and 100 ns molecular dynamics simulations confirmed stable peptide–Keap1 interactions, particularly for FRF. Cellular assays demonstrated that FRF and RWL significantly protected HepG2 cells against H₂O₂-induced oxidative damage by restoring antioxidant enzyme activities (SOD, CAT, and GSH-Px). Collectively, this study establishes a systematic workflow for discovering plant-derived antioxidant peptides and supports the sustainable valorization of PSM as a functional food ingredient. Full article

(1) Background: Bioactive peptides from marine and plant sources show neuroprotective potential, yet how their combination ratios affect memory regulation via the gut–brain axis remains unclear. This study investigated the effects of different ratios of marine peptide QMDDQ (Glutamine-Methionine-Aspartate-Aspartate-Glutamine) and plant peptide AGLPM (Alanine-Glycine-Leucine-Proline-Methionine) on scopolamine-induced memory impairment in mice. (2) Methods: Cognitive function was assessed using the Morris water maze and novel object recognition tests. Nissl staining, microplate-based assays for acetylcholine (ACh) content and acetylcholinesterase (AChE) activity, Western blotting for neurotrophic factors, LC-MS/MS-based intestinal peptide profiling, and HPLC-based brain amino acid analysis were performed. (3) Results: The 1:1 ratio most effectively restored learning and memory, regulated hippocampal cholinergic function, mitigated neuronal damage, and elevated BDNF, NGF, and NTF-3 expression. In the gut, peptides were hydrolyzed into glutamate- and proline-rich fragments, which influenced brain amino acid balance by elevating glutamate and proline levels while reducing NH₃-related signaling. (4) Conclusions: These results highlight the ratio-dependent efficacy of QMDDQ-AGLPM combinations and provide evidence for a gut peptide remodeling-brain metabolic link relevant to cognitive impairment. Full article

Deep-sea mollusks represent untapped resources for searching novel biologically active peptides effectual against many chronic diseases. Here we presented the identification of four novel angiotensin I-converting enzyme (ACE) inhibitory peptides from the deep-sea mollusk Gigantidas platifrons by using a combined approach of peptidomics and virtual screening. Fifteen protein hydrolysates from five deep-sea macroorganisms were prepared using three different proteases and were determined for their ACE inhibitory activities. Pepsin hydrolysate of G. platifrons protein (GPp) demonstrated the highest inhibition rate against ACE at 400 μg/mL. Then, targeted investigation was conducted on the GPp with peptidomic profiling; more than 3000 peptides were de novo identified, which were then subject to virtual screening using the docking software Smina. Subsequently, 29 peptides were selected and synthesized based on the affinity threshold and the interactions with ACE active sites. More than 58% peptides were biologically active, showing more than 50% inhibition to ACE at 400 μM. Four peptides, LAAHFAR, YAAPYR, NGAGPYGRP, and FTTFGK, exhibited low micromolar inhibition. The most potent peptide, LAAHFAR with an IC₅₀ of 6.01 ± 1.06 μM, was subject to molecular dynamics simulations for revealing atomistic interaction analysis. LAAHFAR forms comprehensively stable hydrogen bonds with the classic active site of ACE, and its N terminal arginine residue is anchored by additional hydrogen bonding to Cys370, Asp377, and Thr372. This study highlights deep-sea mollusks as an important source of novel ACE inhibitory peptides, contributing to the development of new therapeutic ingredients or functional food agents against hypertension. Full article

Complement activation has been implicated in many kidney diseases, but it remains unclear whether urinary complement-derived peptides reflect kidney function beyond albuminuria and predict disease progression. We analyzed mass spectrometry-based urinary peptidomics data from 10,939 individuals with chronic kidney disease and healthy controls. Fifty-eight complement-derived peptides were identified, predominantly from complement factor B (CFB) and C3. Of these, fifty-two were significantly related to estimated glomerular filtration rate (eGFR) independently of albuminuria, mostly inversely. Several C3- and CFB-derived peptides were also associated with specific kidney disease etiologies. In a longitudinal analysis of 3964 individuals (median follow-up 2.91 years), 18 of these peptides were significantly related to a major adverse kidney event (MAKE, defined as ≥40% eGFR decline, end-stage kidney disease or death) after adjustment for clinical covariates, indicating prognostic information beyond traditional risk markers. In the independent test cohort, combining these peptides in a machine learning-based model and adding the resulting risk score to clinical parameters significantly improved MAKE prediction (AUC 0.801 vs. 0.778, p = 0.031). Thus, urinary complement-derived peptides provide independent and clinically relevant information on kidney function and disease progression, supporting their potential value in the identification of high-risk patients and guiding more personalized therapy. Full article

Leuenbergeria bleo (Kunth) DC. (Cactaceae), previously classified as Pereskia bleo, represents a phylogenetically basal cactus species with a disjunct distribution across Central America, Southeast Asia, and southern China. Phytochemical investigations have traditionally emphasized small-molecule secondary metabolites, including phenolics, alkaloids, and terpenoids, which contribute to antioxidant and anti-cancer activities. However, recent peptidomic analyses have expanded this chemical space through the discovery of bleogens, a family of hyper-stable, cysteine-rich microproteins with specific antifungal and wound-healing properties. This review systematically integrates botanical characteristics, ethnomedicinal applications, and pharmacological profiles, providing a comparative analysis of the plant’s small-molecule constituents versus its peptidyl biologics. It identifies the co-existence of these distinct chemical classes as a defining feature of the plant’s efficacy while highlighting the need for future research into their potential interactions. Full article

The global rise in antimicrobial resistance among the ESKAPE pathogens represents a major challenge to public health. Here, we report the broad-spectrum antibacterial activity of the synthetic antimicrobial and pore-forming peptide C14R against all six ESKAPE species. Using a radial diffusion assay and resazurin-based viability testing, C14R exhibited a potent bactericidal effect with minimum inhibitory concentrations (MICs), defined as the lowest concentration of an antimicrobial agent that completely inhibits visible growth of planktonic microorganisms, ranging from 3.4 µg/mL (Enterococcus faecium, vancomycin-resistant) to 45.2 µg/mL (Klebsiella quasipneumoniae, ESBL). C14R also inhibited biofilm formation by Gram-positive pathogens, with minimum biofilm inhibitory concentrations (MBICs), referring to the minimal concentration required to prevent the development of biofilms, of 15.0 µg/mL (Staphylococcus aureus, MRSA) and 22.0 µg/mL (E. faecium, VRE), whereas Gram-negative biofilms showed higher tolerance. Together, these findings demonstrate that C14R retains high activity against multidrug-resistant ESKAPE strains, highlighting its potential as a lead compound for the development of next-generation antimicrobial drugs to expand the portfolio of available antibiotics and brace health systems against emerging severe infections. Full article

Sea cucumber viscera by-products are abundant but remain underutilized. Although the development of umami peptides from marine by-products has been well-reported, sea cucumber viscera have received less attention. In this study, an umami-rich hydrolysate was prepared from sea cucumber viscera through synergistic dual-enzyme hydrolysis. Under optimal conditions, the co-hydrolysis using Flavourzyme and aminopeptidase yielded extraction rates of 69.38% for solids, 67.29% for protein, and 66.96% for total sugar, and produced a 1.75-fold higher umami signal intensity (electronic tongue) than the single-enzyme (Flavourzyme) hydrolysate. The target umami fraction was enriched through sensory-guided separation combined with ultrafiltration and ion-exchange chromatography. Thirty-three umami peptides, predominantly derived from actin hydrolysis, were identified in this fraction via peptidomics and virtual screening. Based on docking simulations against the umami receptor T1R1/T1R3, two peptides (DFLDDGPG and SDTGNFGF) with the lowest docking scores were selected. The predictions revealed that two peptides bind to the T1R3 subunit via hydrogen bonds and π-related interactions. The umami-enhancing effect of peptide DFLDDGPG in salty systems was demonstrated by a trained panel (n = 10) across concentration ranges of 0.1–1.0 mg/mL peptide and 0.1–1.0% NaCl, with a positive correlation validated by RSM and ANOVA (p < 0.05). This study identified novel umami peptides from sea cucumber by-products as promising candidates for natural, low-sodium flavor enhancers. Full article