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1.
Food Res Int ; 195: 114898, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39277214

RESUMEN

The main objective of this study was to assess the ability of the NEar Real Digestive Tract (NERDT), a computer-controlled biomimetic in vitro digestion system that considers the biomechanics of the stomach, to reproduce physiologically relevant features of skimmed milk gastric digestion. A second objective was to evaluate the influence of pepsin on the gastric coagulation and emptying of milk proteins from experiments performed with and without pepsin. A mass balance model over the stomach, assuming a perfectly stirred reactor behaviour, has been developed. The results show that the NERDT can adequately reproduce the targeted kinetics of gastric acidification and emptying, with a sieving effect that naturally leads to a delayed emptying of caseins. Milk coagulated earlier and more chyme was emptied towards the end of the experiments in the presence of pepsin than without, hence illustrating the key influence of pepsin on the gastric coagulation of caseins and subsequent hydrolysis and emptying of dairy particles. Overall, this study shows that the NERDT can be adequately controlled to achieve desired gastric digestion conditions, and appears to be a very useful tool to further improve the knowledge of the gastric digestion behaviour of complex foods such as milk.


Asunto(s)
Biomimética , Digestión , Leche , Pepsina A , Digestión/fisiología , Animales , Pepsina A/metabolismo , Humanos , Leche/química , Biomimética/métodos , Modelos Biológicos , Concentración de Iones de Hidrógeno , Vaciamiento Gástrico/fisiología , Caseínas/metabolismo , Estómago/fisiología , Cinética , Proteínas de la Leche/metabolismo
2.
Neurogastroenterol Motil ; : e14905, 2024 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-39223797

RESUMEN

BACKGROUND AND PURPOSE: The definitive diagnosis of gastroesophageal reflux disease (GERD) often requires invasive investigations like upper gastrointestinal endoscopy or reflux monitoring. We aimed to explore the relationship between salivary pepsin and GERD and its value as a non-invasive diagnostic tool. METHODS: Databases (PubMed, Web of Science, Cochran Library, and EMBASE) were searched from their inception to January 22, 2024 to explore the correlation of salivary pepsin with GERD. The meta-analysis data retrieved were summarized, including the salivary pepsin concentration, sensitivity of diagnosis (SEN), specificity of diagnosis (SPE), negative likelihood ratio, positive likelihood ratio, diagnostic odds ratio, and receiver operating characteristic (ROC) curve. RESULTS: The meta-analysis comparing salivary pepsin concentration in two groups (proven GERD and non-GERD) with 18 studies revealed that the proven GERD group had higher salivary pepsin concentration than the non-GERD group (SMD = 1.74 [95% CI 1.14-2.34]). The meta-analysis of salivary pepsin diagnostic value for proven GERD incorporated 23 studies. The results showed pooled SEN (0.73 [95% CI 0.66-0.80]), SPE (0.72 [95% CI 0.65-0.78]), positive likelihood ratio (2.61 [95% CI 2.02-3.39]), negative likelihood ratio (0.37 [95% CI 0.28-0.50]), diagnostic odds ratio (7.03 [95% CI 4.24-11.66]) and area under the SROC curve (0.79 [95% CI 0.75-0.82]). CONCLUSION: GERD patients presented a higher salivary pepsin concentration. Salivary pepsin is both sensitive and specific in identifying GERD, making it a promising non-invasive marker for diagnosis.

3.
Comp Biochem Physiol B Biochem Mol Biol ; 275: 111031, 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39260767

RESUMEN

The hake fishery plays a crucial role due to its significant economic impact. The genus Merluccius includes 12 extant species found along the coasts of the Americas, Europe, and Africa. However, research on their digestive physiology and the enzymes involved in digestion, including proteases, remains limited. Proteases play a key role in protein digestion, a vital process for all living organisms. This study focused on screening the genomes of eight Merluccius spp. for eight specific proteases previously identified in Merluccius polli. Additionally, the study conducted biochemical analyses of proteases found in the stomach and intestine of Pacific whiting fish (Merluccius productus), comparing the results with the genomic findings. The analysis revealed that proteases across Merluccius spp. are conserved, although with slight variations, particularly in chymotrypsin and aspartic proteases. Biochemical characterization of M. productus identified at least three main proteases in the stomach, active at acidic pH, and at least seven proteases in the intestine, active at alkaline pH, as determined by electrophoresis. Further investigation, including specific inhibition studies, determination of molecular mass, and assessment of pH and temperature preferences for catalysis, revealed that one of the stomach proteases functioning at acidic pH likely belongs to the acid peptidase class, likely pepsin. Similarly, analysis of proteases active at alkaline pH indicated the presence of a chymotrypsin and a trypsin, consistent with genomic findings in M. productus. These results are important as they provide insights into the digestive physiology of Merluccius spp., contributing to a better understanding of their nutritional needs.

4.
Molecules ; 29(15)2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-39124857

RESUMEN

The superfamily of acid proteases has two catalytic aspartates for proteolysis of their peptide substrates. Here, we show a minimal structural scaffold, the structural catalytic core (SCC), which is conserved within each family of acid proteases, but varies between families, and thus can serve as a structural marker of four individual protease families. The SCC is a dimer of several structural blocks, such as the DD-link, D-loop, and G-loop, around two catalytic aspartates in each protease subunit or an individual chain. A dimer made of two (D-loop + DD-link) structural elements makes a DD-zone, and the D-loop + G-loop combination makes a psi-loop. These structural markers are useful for protein comparison, structure identification, protein family separation, and protein engineering.


Asunto(s)
Dominio Catalítico , Modelos Moleculares , Péptido Hidrolasas/química , Péptido Hidrolasas/metabolismo , Secuencia de Aminoácidos , Conformación Proteica
5.
Cancers (Basel) ; 16(15)2024 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-39123415

RESUMEN

The significance of extraesophageal reflux as a risk factor in lung adenocarcinoma has been understudied. In this study, we investigated whether extraesophageal reflux leads to higher pepsin concentrations in bronchoalveolar lavage (BAL) in patients with lung adenocarcinoma compared to controls. Subjects were recruited from non-smoker patients (lifelong non-smokers and ex-smokers with more than 5 years of non-smoking history) who had undergone bronchoscopy due to pulmonary abnormalities on a CT scan and met the inclusion criteria. Based on histological verification of the lung process, the patients were divided into three groups: (1) lung adenocarcinoma, (2) pulmonary metastases, and (3) lung sarcoidosis. Lung adenocarcinoma cases were further categorized as central or peripheral. BAL samples collected during bronchoscopy were quantitatively analyzed by enzyme-linked immunosorbent assay (ELISA) to measure pepsin levels. No statistically significant difference in pepsin concentration was observed between the lung adenocarcinoma group and control groups (p = 0.135). After excluding hemorrhagic BAL samples, the pepsin concentration was significantly the lowest in patients with lung adenocarcinoma (p = 0.023) compared to the control groups. The results of the study do not support the hypothesis of a higher occurrence of extraesophageal reflux (evaluated as the amount of pepsin in BAL) in non-smoker patients with lung adenocarcinoma.

6.
Animals (Basel) ; 14(15)2024 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-39123703

RESUMEN

Organic acids (OAs) are employed in animal feed to regulate gastrointestinal disorders and diarrhoea thanks to their ability to modulate the gastrointestinal environment and their antimicrobial capacity. However, there is not enough evidence regarding the most adequate OA and its effectiveness in rabbit farming. Therefore, the aim of this study was to screen and evaluate the response of young rabbits to six OAs, administered via drinking water, at three different concentrations (pH levels). Organic acids (acetic, ACET; formic, FOR; propionic, PROP; lactic, LAC; citric, CIT; and butyric, BUT) were tested at three concentrations (pH 3, 4, and 5). A negative control (CON; non-acidified water) was also included. We used 240 weaned rabbits (28 days old) divided into 2 batches. In each batch, animals were randomly allocated to 1 of the 19 experimental treatments and were housed in group cages of 6 animals per cage, treatment, and batch. Among the 240 rabbits, an additional cage with 6 animals was included to determine the initial physiological state of the animals. All animals were fed with commercial pelleted feed throughout the whole experiment. The duration of the study was 7 days, until 35 days of age. At 31 and 35 days of age, in each batch, three animals per day and treatment were slaughtered. The pH of the digestive contents in the fundus, antrum, duodenum, jejunum, ileum, and cecum, as well as the gastric pepsin enzyme activity, was measured. Water and feed consumption per cage and individual body weight (BW) were recorded daily. The type and dosage of OAs affected water intake. ACET 3, PROP 3, and BUT 3 reduced water intake compared to CON, negatively impacting feed intake and weight gain. FOR and CIT acids led to the highest BW and weight gain at 35 days, compared to PROP, LAC, and BUT (p < 0.05); showing ACET intermediate values. While OAs had limited effects on gastric and small intestine pH, acidified water at pH 4 and 5 lowered ileum and caecum pH (p < 0.05) compared to pH 3. Acidified water at pH 4 showed the highest (p < 0.05) pepsin activity compared to pH 3 and pH 5. Considering the limited sample size and short-term assessment period of our screening test, the OAs with the highest potential for use in post-weaning rabbits were FOR, ACET, and CIT at pH 4. The selected combinations did not exhibit any early adverse effects in young rabbits. These results should be further confirmed in a broader population of animals. It would also be advisable to extend the application of OAs over longer periods to evaluate their effects throughout the entire growing period of rabbits.

7.
J Thorac Dis ; 16(7): 4678-4684, 2024 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-39144358

RESUMEN

Patients undergoing lung resection may be at risk of gastroesophageal reflux (GER) and silent aspiration following surgery. Defining high-risk patients may lead to prevention strategies for silent aspiration and subsequent exacerbation of underlying pulmonary disease. A pilot study of 50 patients was performed to investigate postoperative gastroesophageal reflux disease (GERD) symptoms and the pepsin concentration in saliva. Patients answered a questionnaire concerning GERD symptoms before lung surgery and at the time of discharge. Saliva samples were obtained before surgery, on the third postoperative day and at discharge. Pepsin concentration was measured with Peptest. The pepsin concentration in saliva following resection was significantly elevated on postoperative day 3, but it returned to the baseline level at discharge. Patients undergoing resection of four or more lung subsegments had a continuously elevated pepsin concentration in saliva on postoperative day 3 [mean difference 65.63 ng/mL, 95% confidence interval (CI): 9.130-122.1] and at discharge (mean difference 76.22 ng/mL, 95% CI: 19.72-132.7). Patients with a >10% reduction of forced expiration volume in one second also had a continuous elevated pepsin concentration from the 3rd postoperative day. Lung resection resulted in elevated pepsin concentration in the saliva, which persisted in patients who received resections equivalent to or more than right middle lobectomy in volume. Resection of large volumes of lung may lead to anatomical changes and changes in breathing patterns and result in GER.

8.
Int J Biol Macromol ; 279(Pt 2): 135178, 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39214215

RESUMEN

Tetrahydrocurcumin (THC), as a novel food supplement, has generated significant interests for its potential impact on health and nutrition. Pepsin serves as the primary enzyme involved in the digestive mechanism. This research investigated the conformational and functional alterations of pepsin induced by THC using multispectral techniques and computer simulations. The results showed that THC enters the cavity of pepsin, in which hydrophobic forces play a major role. The binding constant is 1.044 × 104 M-1 at 310 K. The upregulation or downregulation effect of THC on pepsin activity depends on its concentration. Molecular docking outcomes indicated that THC was encapsulated by various amino acids and established H-bonds with Tyr189 and Ser294, revealing that hydrogen bonds also contribute to maintaining the stability of THC-pepsin complex. In addition, the altered activity of pepsin may be related to the interaction between THC and the amino acids at the active site (Asp32) according to energy contribution results. 3D fluorescence spectroscopy, CD spectra and molecular dynamic simulations show that THC causes conformational changes in pepsin. The existence of THC makes pepsin structure to be less dense, leading to the decrease of energy traps. This suggests that pepsin becomes conformationally more suitable to bind to THC.

9.
Respir Med ; 233: 107781, 2024 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-39182853

RESUMEN

AIM: Pepsin is an enzyme that helps digest protein secreted only from the gastric chief cell in an inactive state. Pepsin is a good marker for acidic gastroesophageal reflux (GER). Its presence in sputum or saliva is considered pathologic. In GER, cough is stimulated by broncho-esophageal neurogenic reflex and aspiration of gastric contents into the airways. GER is the most common cause of cough. Gastric acid reflux is also thought to play a role in Interstitial Lung Disease (ILD) etiology. In many studies, pepsin and bile acid levels in bronchial lavage were high in patients with interstitial lung disease and chronic cough. In our study, we aimed to evaluate pepsin levels in bronchial lavage in patients with ILD and chronic cough and to investigate the relationship between symptoms and reflux treatment. METHODS: Between January 2021 and February 2022, 212 patients who underwent bronchoscopy in our tertiary clinic were evaluated. These patients were divided into three groups: 52 patients with interstitial lung disease, 81 patients with chronic cough, and 79 patients who underwent bronchoscopy with a pre-diagnosis of lung cancer as the control group. Bronchial lavage obtained by bronchoscopy was analyzed for pepsin levels. RESULTS: Shortness of breath and cough were the most common symptoms in all three groups. Pepsin levels were 16.71 ± 8.6 ng/ml in the chronic cough group, 15.6 ± 8.9 ng/ml in the ILD group, and 10.58 ± 5.4 ng/ml in the lung cancer (control) group. Pepsin levels in the ILD and chronic cough group were statistically significantly higher than in the lung cancer group (p:0.00). There was no statistical difference between the ILD group and the chronic cough group regarding pepsin levels. It was found that pepsin levels were lower in the three groups who received anti-reflux treatment. There was no difference in pepsin levels between ILD subgroups. CONCLUSION: Pepsin levels in bronchial lavage were higher in the ILD and chronic cough groups. This suggests that reflux may be involved in the etiology of chronic cough and ILD. Low pepsin values in patients receiving anti-reflux therapy have shown that occult reflux may occur. In our study, the high level of pepsin in bronchial lavage, especially in the chronic cough and ILD group, may be instructive in the etiology and treatment planning of the disease.


Asunto(s)
Tos , Reflujo Gastroesofágico , Enfermedades Pulmonares Intersticiales , Pepsina A , Humanos , Tos/metabolismo , Tos/etiología , Pepsina A/análisis , Pepsina A/metabolismo , Enfermedades Pulmonares Intersticiales/metabolismo , Enfermedades Pulmonares Intersticiales/complicaciones , Enfermedad Crónica , Masculino , Femenino , Persona de Mediana Edad , Reflujo Gastroesofágico/complicaciones , Reflujo Gastroesofágico/metabolismo , Anciano , Líquido del Lavado Bronquioalveolar/química , Lavado Broncoalveolar/métodos , Broncoscopía/métodos , Biomarcadores/metabolismo , Biomarcadores/análisis , Tos Crónica
10.
Food Chem ; 458: 140175, 2024 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-38964099

RESUMEN

D-amino acids can affect the action of digestive enzymes, hence the protein digestion. In this work the behaviour of the main stomach and gut digestive enzymes (pepsin, trypsin, and chymotrypsin) in the presence of D-amino acids in the protein chain was monitored over time using a model peptide, Ac-LDAQSAPLRVYVE-NH2 (belonging to ß-lactoglobulin, position 48-60), where L-amino acids were systematically substituted by D-amino acids. The results showed several changes in the behaviour of digestive enzymes, not only when the D-amino acids are inserted at the specific cleavage sites (after Val-57), but in some cases also when in distant positions. The effect seemed more pronounced in the case of pepsin rather than the gut enzymes, possibly indicating a better resilience of the upper gut phase of digestion to racemization. These results demonstrated that racemization could impair nutritional value by slowing down digestibility and has different effects according to the enzyme/amino acids involved.


Asunto(s)
Aminoácidos , Quimotripsina , Digestión , Pepsina A , Péptidos , Tripsina , Aminoácidos/química , Aminoácidos/metabolismo , Tripsina/química , Tripsina/metabolismo , Péptidos/química , Péptidos/metabolismo , Quimotripsina/química , Quimotripsina/metabolismo , Pepsina A/química , Pepsina A/metabolismo , Secuencia de Aminoácidos , Animales , Humanos , Lactoglobulinas/química , Lactoglobulinas/metabolismo , Modelos Biológicos
11.
Artículo en Inglés | MEDLINE | ID: mdl-39082884

RESUMEN

OBJECTIVE: The pathogenic mechanism underlying the effects of acidic pepsin in laryngeal cancer remains unclear. This study investigated whether acidic pepsin influences Glut-1 expression and glycolytic activity in laryngeal carcinoma cells and whether it plays a role in the growth and migration of these cells through glycolysis. STUDY DESIGN: In vitro study. SETTING: A university-affiliated hospital. METHODS: Laryngeal carcinoma TU 212 and TU 686 cells were treated with acidic pepsin and 2-deoxy-d-glucose (2-DG), then transfected with Glut-1 small interfering RNA (siRNA). Glucose uptake was detected by a radioimmunoassay counter, lactate secretion was detected by a lactic acid kit, and Glut-1 expression was detected by western blotting. Cell viability, migration and invasion, and clonal formation were assessed using the Cell Counting Kit-8, Transwell chamber, and clonal formation assays, respectively. RESULTS: Acidic pepsin significantly increased Glut-1 expression in laryngeal carcinoma cells compared with the control group (P < .01). It also significantly enhanced 18F-fluorodeoxyglucose (Cin/Cout) uptake, lactate secretion, cell viability, migration, invasion, and clonal formation in laryngeal carcinoma cells compared with the control group (P < .01). The glycolytic inhibitor 2-DG and Glut-1 siRNA significantly reversed the effects of acidic pepsin on laryngeal carcinoma cells (P < .01). CONCLUSION: Acidic pepsin enhances the growth and migration of laryngeal carcinoma cells by upregulating Glut-1, thus promoting glycolysis.

12.
Polymers (Basel) ; 16(14)2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39065392

RESUMEN

Starch is a promising polymer for creating novel microparticulate systems with superior biocompatibility and controlled drug delivery capabilities. In this study, we synthesized polyethylene glycol (PEG)-modified starch microparticles and encapsulated folic acid using a solvent-mediated acid-base precipitation method with magnetic stirring, which is a simple and effective method. To evaluate particle degradation, we simulated physiological conditions by employing an enzymatic degradation approach. Our results with FTIR and SEM confirmed the successful synthesis of starch-PEG microparticles encapsulating folic acid. The average size of starch microparticles encapsulating folic acid was 4.97 µm and increased to 6.01 µm upon modification with PEG. The microparticles were first exposed to amylase at pH 6.7 and pepsin at pH 1.5 at different incubation times at physiological temperature with shaking. Post-degradation analysis revealed changes in particle size and morphology, indicating effective enzymatic degradation. FTIR spectroscopy was used to assess the chemical composition before and after degradation. The initial FTIR spectra displayed characteristic peaks of starch, PEG, and folic acid, which showed decreased intensities after enzymatic degradation, suggesting alterations in chemical composition. These findings demonstrate the ongoing development of starch-PEG microparticles for controlled drug delivery and other biomedical applications and provide the basis for further exploration of PEG-starch as a versatile biomaterial for encapsulating bioactive compounds.

13.
ACS Appl Mater Interfaces ; 16(30): 39241-39250, 2024 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-39024494

RESUMEN

Biological enzyme-driven degradation of environmental pollutants has attracted widespread attention because it is ecofriendly and highly efficient. Immobilized enzyme technology has emerged as a promising technique in enzymology that addresses the limitations associated with free enzymes. Traditional solid-loaded enzyme substrates are often affected by blockages and restricted substrate accessibility. In this study, we synthesized an efficient heterogeneous pepsin catalyst, named PEP@M-MIL100(Fe), by covalently combining carboxylated ferrite structural expanded metal-organic frameworks with pepsin. This catalyst demonstrated excellent environmental adaptability and remarkable catalytic degradation capabilities. Notably, it rapidly degraded the persistent microplastic pollutant diisononyl phthalate (DINP) within just 150 min, with a removal efficiency of up to 95.88%. Impressively, even after 10 consecutive uses, the catalyst maintained its high performance. We proposed an innovative steady-state heterogeneous enzyme-catalyzed degradation mechanism, i.e., diffusion (D)-absorption (A)-binding (B)-reaction (R)-degradation (D)-link mechanism, which emphasizes the influence of substrate diffusion rates in this process. This work presents the first successful application of pepsin to DINP degradation and offers a sustainable and effective approach for addressing contemporary pollution challenges.


Asunto(s)
Ésteres , Estructuras Metalorgánicas , Pepsina A , Ácidos Ftálicos , Estructuras Metalorgánicas/química , Ácidos Ftálicos/química , Pepsina A/química , Pepsina A/metabolismo , Ésteres/química , Catálisis , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Contaminantes Ambientales/química
14.
MAbs ; 16(1): 2379903, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39077932

RESUMEN

A sensitive and specific bioanalytical method was required to measure the exposure of a LAGA-mutated surrogate mouse IgG2a monoclonal antibody in mouse plasma, but the lack of highly specific reagents for the LAGA mutant hindered the development of a ligand-binding assay. Equally problematic is that no sensitive unique tryptic peptides suitable for quantitative mass spectrometric analysis could be identified in the mIgG2a complementarity-determining regions. To overcome these challenges, a trypsin alternative pepsin, an aspartic protease, was systematically investigated for its use in digesting the mutated mIgG2a antibody to allow generation of signature peptides for the bioanalytical quantification purpose. After a series of evaluations, a rapid one-hour pepsin digestion protocol was established for the mutated Fc backbone. Consequently, a new pepsin digestion-based liquid chromatography-tandem mass spectrometry (LC/MS/MS) method was successfully developed to support the mouse pharmacokinetic (PK) sample analysis. In brief, robust and reproducible C-terminal cleavage of both leucine and phenylalanine near the double mutation site of the mutated mIgG2a was accomplished at pH ≤2 and 37°C. Combined with a commercially available rat anti-mIgG2a heavy-chain antibody, the established immunoaffinity LC/MS/MS assay achieved a limit of quantitation of 20 ng/mL in the dynamic range of interest with satisfactory assay precision and accuracy. The successful implementation of this novel approach in discovery PK studies eliminates the need for tedious and costly generation of specific immunocapturing reagents for the LAGA mutants. The approach should be widely applicable for developing popular LAGA mutant-based biological therapeutics.


Asunto(s)
Inmunoglobulina G , Pepsina A , Espectrometría de Masas en Tándem , Animales , Inmunoglobulina G/genética , Inmunoglobulina G/inmunología , Espectrometría de Masas en Tándem/métodos , Ratones , Cromatografía Liquida/métodos , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/genética , Ratas , Mutación , Cromatografía de Afinidad/métodos
15.
Int J Biol Macromol ; 277(Pt 1): 134178, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39067726

RESUMEN

Pepsin as an aspartic acid protease member and one of the three foremost proteolytic enzymes in the digestive system is essential to be detected. An electrochemically polymerized tyrosine film on carbon paste electrode (pTyr/CPE) has been synthesized by electro-polymerization donating an affordable electrochemical sensor to sense salivary pepsin as a diagnostic technique for gastroesophageal reflux disease (GRD) due to saliva collection is non-invasive and relatively comfortable. The pTyr/CPE was applied for Voltammetric sensing of pepsin and its quantification in phosphate buffer solution of pH 2.0 (PBS). Scanning electron microscopy (SEM) was conducted to learn the surface morphology. Cyclic voltammetry (CV), differential pulse voltammetry (DPVs), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) were developed to realize the electrocatalytic activity of the sensor. The pTyr/CPE proceeded as a sensitive detector to pepsin with two linear ranges from 1 to 20 & 20 to 100 ng/mL donating two limits of detection as 0.5 & 0.09 ng/mL, respectively, and high selectivity toward pepsin, as well as stability and fast response of 1.5 s. Consequently, it is guessed that the pTyr/CPE sensor could be supportive for the initial diagnosis of GRD through the detection of pepsin in saliva. Finally, we quantified the pepsin levels in saliva samples of LPR patients (n = 2), showing that the results were agreeable with those from the electrochemical sensor.


Asunto(s)
Técnicas Biosensibles , Técnicas Electroquímicas , Pepsina A , Saliva , Pepsina A/análisis , Saliva/química , Humanos , Técnicas Electroquímicas/métodos , Técnicas Biosensibles/métodos , Electrodos , Tirosina/análisis , Espectroscopía Dieléctrica , Reflujo Gastroesofágico/diagnóstico , Límite de Detección
16.
Biochem Biophys Res Commun ; 732: 150401, 2024 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-39033554

RESUMEN

The pathophysiology of laryngopharyngeal reflux (LPR) and its impact on the vocal fold is not well understood, but may involve acid damage to vocal fold barrier functions. Two different components encompass vocal fold barrier function: the mucus barrier and tight junctions. Mucus retained on epithelial microprojections protects the inside of the vocal fold by neutralizing acidic damage. Tight junctions control permeability between cells. Here we developed an in vitro experimental system to evaluate acidic injury and repair of vocal fold barrier functions. We first established an in vitro model of rat vocal fold epithelium that could survive at least one week after barrier function maturation. The model enabled repeated evaluation of the course of vocal fold repair processes. Then, an injury experiment was conducted in which vocal fold cells were exposed to a 5-min treatment with acidic pepsin that injured tight junctions and cell surface microprojections. Both of them healed within one day of injury. Comparing vocal fold cells treated with acid alone with cells treated with acidic pepsin showed that acidic pepsin had a stronger effect on intercellular permeability than acid alone, whereas pepsin had little effect on microprojections. This result suggests that the proteolytic action of pepsin has a larger effect on protein-based tight junctions than on phospholipids in microprojections. This experimental system could contribute to a better understanding of vocal fold repair processes after chemical or physical injuries, as well as voice problems due to LPR pathogenesis.


Asunto(s)
Pepsina A , Uniones Estrechas , Pliegues Vocales , Animales , Pepsina A/metabolismo , Pepsina A/farmacología , Pliegues Vocales/efectos de los fármacos , Pliegues Vocales/patología , Pliegues Vocales/metabolismo , Pliegues Vocales/lesiones , Ratas , Uniones Estrechas/metabolismo , Uniones Estrechas/efectos de los fármacos , Ratas Sprague-Dawley , Masculino , Reflujo Laringofaríngeo/metabolismo , Reflujo Laringofaríngeo/tratamiento farmacológico , Reflujo Laringofaríngeo/patología , Concentración de Iones de Hidrógeno
17.
J Agric Food Chem ; 72(26): 14844-14850, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38885440

RESUMEN

The 11S globulin legumin typically accounts for approximately 3% of the total protein in common beans (Phaseolus vulgaris). It was previously reported that a legumin peptide of approximately 20 kDa is resistant to pepsin digestion. Sequence prediction suggested that the pepsin-resistant peptide is located at the C-terminal end of the α-subunit, within a glutamic acid-rich domain, overlapping with a chymotrypsin-resistant peptide. Using purified legumin, the peptide of approximately 20 kDa was found to be resistant to pepsin digestion in a pH-dependent manner, and its location was determined by two-dimensional gel electrophoresis and LC-MS-MS. The location of the chymotrypsin-resistant peptide was confirmed by immunoblotting with peptide-specific polyclonal antibodies. The presence of a consensus site for proline hydroxylation and arabinosylation, the detection of hydroxyproline residues, purification by lectin affinity chromatography, and a difference in electrophoretic migration between the chymotrypsin- and pepsin-resistant peptides suggest the presence of a large O-glycan within these peptides.


Asunto(s)
Secuencia de Aminoácidos , Quimotripsina , Pepsina A , Péptidos , Phaseolus , Phaseolus/química , Pepsina A/química , Pepsina A/metabolismo , Quimotripsina/química , Quimotripsina/metabolismo , Péptidos/química , Péptidos/aislamiento & purificación , Leguminas/química , Espectrometría de Masas en Tándem , Proteínas de Plantas/química , Proteínas de Plantas/aislamiento & purificación , Proteínas de Plantas/metabolismo
18.
Food Res Int ; 190: 114562, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38945563

RESUMEN

The structural and functional properties of whey-quercetin and whey hydrolysate-quercetin conjugates synthesized using alkaline and free radical-mediated methods (AM and FRM) coupled with sonication were studied. FTIR showed new peaks at 3000-3500 cm-1 (N-H stretching regions) and the 1000-1100 cm-1 region with the conjugates. Conjugation increased the random coils and α-helix content while decreasing the ß-sheets and turns. It also increased the particle size and surface hydrophobicity which was significantly (p < 0.05) higher in AM than FRM conjugates. AM conjugates had higher radical scavenging activity but lower quercetin content than FRM conjugates. Overall, the functional properties of whey-quercetin conjugates were better than whey hydrolysate-quercetin conjugates. However, hydrolysate conjugates had significantly higher denaturation temperatures irrespective of the method of production. Sonication improved the radical scavenging activity and quercetin content of FRM conjugates while it decreased both for AM conjugates. This study suggested that whey-quercetin conjugates generally had better quality than whey hydrolysate conjugates and sonication tended to further improve these properties. This study highlights the potential for using camel whey or whey hydrolysate-quercetin conjugates to enhance the functional properties of food products in the food industry.


Asunto(s)
Camelus , Interacciones Hidrofóbicas e Hidrofílicas , Quercetina , Sonicación , Quercetina/química , Animales , Hidrolisados de Proteína/química , Suero Lácteo/química , Antioxidantes/química , Proteína de Suero de Leche/química , Depuradores de Radicales Libres/química , Espectroscopía Infrarroja por Transformada de Fourier , Radicales Libres/química , Tamaño de la Partícula , Concentración de Iones de Hidrógeno
19.
J Med Food ; 27(5): 460-465, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38695854

RESUMEN

The principal mechanisms surrounding gastrointestinal (GI) side effects due to chemotherapy are unclear, whereas the information regarding symptom management of patients with esophageal cancer post-esophagectomy is lacking. Esophagectomy patients are left with significant anatomical changes to the GI tract, including the cutting of the vagus nerve, which regulates gastric secretions, gastric acid pH, and motility. A 76-year-old male patient self-referred himself to the clinical dietitian for nutritional management of chronic nausea, fatigue, weight loss, and dumping syndrome 9 months post-esophagectomy, which was not responsive to medications. A physical functional nutritional assessment with evaluation of diet history and elimination suggested gastric hypochlorhydria. Gastric acid is needed for the active absorption of iron, zinc, B complex vitamins, especially B12, and digestion of consumed proteins. A digestive supplement, betaine hydrochloric acid with pepsin (BHClP), was introduced, and the patient ingested 1 capsule containing 500 mg betaine hydrochloride and 23.5 mg pepsin prior to protein-containing meals and reported a substantial decrease in GI symptoms while eating a regular diet with no limitations. He gained necessary weight and energy for daily activities. After a few months, the patient discontinued BHClP, and GI symptoms and dumping syndrome returned, leading to a loss of 7.5% of his body weight. The patient reinitiated the supplement and GI symptoms dissipated, and weight was restored. BHClP provided metabolic therapeutic benefit to optimize the patient's oral intake, preventing further complications and malnutrition. The success with BHClP for this patient case suggests that more research is needed to fully realize the mechanisms and clinical usage.


Asunto(s)
Betaína , Neoplasias Esofágicas , Pepsina A , Humanos , Masculino , Anciano , Neoplasias Esofágicas/tratamiento farmacológico , Betaína/uso terapéutico , Pepsina A/metabolismo , Síndrome de Vaciamiento Rápido/tratamiento farmacológico , Suplementos Dietéticos , Esofagectomía
20.
Food Res Int ; 186: 114161, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38729685

RESUMEN

In this article, the synthesis of antioxidant peptides in the enzymatic hydrolysis of caprine casein was analyzed at three different time points (60 min, 90 min, and 120 min) using immobilized pepsin on activated and modified carbon (AC, ACF, ACG 50, ACG 100). The immobilization assays revealed a reduction in the biocatalysts' activity compared to the free enzyme. Among the modified ones, ACG 50 exhibited greater activity and better efficiency for reuse cycles, with superior values after 60 min and 90 min. Peptide synthesis was observed under all studied conditions. Analyses (DPPH, ß-carotene/linoleic acid, FRAP) confirmed the antioxidant potential of the peptides generated by the immobilized enzyme. However, the immobilized enzyme in ACG 50 and ACG 100, combined with longer hydrolysis times, allowed the formation of peptides with an antioxidant capacity greater than or equivalent to those generated by the free enzyme, despite reduced enzymatic activity.


Asunto(s)
Antioxidantes , Caseínas , Enzimas Inmovilizadas , Glutaral , Cabras , Iridoides , Pepsina A , Péptidos , Antioxidantes/química , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Caseínas/química , Animales , Pepsina A/metabolismo , Pepsina A/química , Glutaral/química , Péptidos/química , Iridoides/química , Hidrólisis , Carbón Orgánico/química
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