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1.
Food Chem ; 366: 130532, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34274702

RESUMO

One major pepsinogen, PG-I, and two minor pepsinogens, PG-II and PG-III were purified from lizardfish stomach by ammonium sulfate precipitation and two chromatographic columns. The three purified PGs migrated as single bands in native-PAGE gels with molecular weights (MW) ranging from 36 to 38 kDa. Each PG was converted to pepsin (P) at pH 2.0, and the MW were determined as 32 kDa (for P-I), 31 kDa (for P-II) and 30 kDa (for P-III). The optimum pH and temperature of pepsins were 2.0-3.5, and 40-50 °C. All 3 pepsins were strongly inhibited by pepstatin A. Divalent cations slightly stimulated the pepsin activities, but ATP had no effect on the pepsins. Purified pepsins were effective in the hydrolysis of various proteins. Km and kcat of the three pepsins for hemoglobin hydrolysis were 107.64-276.61 µM and 18.30-32.68 s-1, respectively. The new pepsins have potential for use in protein food procession and modification.


Assuntos
Pepsina A , Pepsinogênios , Sequência de Aminoácidos , Animais , Peixes/metabolismo , Pepsina A/metabolismo , Pepsinogênios/metabolismo , Estômago
2.
Enzyme Microb Technol ; 150: 109871, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34489030

RESUMO

The present study sought to identify the structural determinants of aspartic protease structural stability and activity at elevated pH. Various hypotheses have been published regarding the features responsible for the unusual alkaline structural stability of renin, however, few structure-function studies have verified these claims. Using pepsin as a model system, and renin as a template for functional and structural alkaline stability, a rational re-design of pepsin was undertaken to identify residues contributing to the alkaline instability of pepsin-like aspartic proteases in regards to both structure and function. We constructed 13 mutants based on this strategy. Among them, mutants D159 L and D60A led to an increase in activity at elevated pH levels (p ≤ 0.05) and E4V and H53F were shown to retain native-like structure at elevated pH (p ≤ 0.05). Previously suggested carboxyl groups Asp11, Asp118, and Glu13 were individually shown not to be responsible for the structural instability or lack of activity at neutral pH in pepsin. The importance of the ß-barrel to structural stability was highlighted as the majority of the stabilizing residues identified, and 39% of the weakly conserved residues in the N-terminal lobe, were located in ß-sheet strands of the barrel. The results of the present study indicate that alkaline stabilization of pepsin will require reduction of electrostatic repulsions and an improved understanding of the role of the hydrogen bonding network of the characteristic ß-barrel.


Assuntos
Pepsina A , Renina , Sequência de Aminoácidos , Ácido Aspártico Endopeptidases/metabolismo , Ligação de Hidrogênio , Pepsina A/metabolismo
3.
Medicine (Baltimore) ; 100(32): e26756, 2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34397878

RESUMO

BACKGROUND: A rapid lateral flow test (Peptest) to detect pepsin in saliva/sputum has been considered as a valuable method for diagnosing laryngopharyngeal reflux (LPR) and gastroesophageal reflux disease (GERD). The aim of this meta-analysis is to analyze the utility of Peptest for diagnosis of LPR and GERD. METHODS: PubMed, EMBASE, and the Cochran Library (from January 1980 to 26 January 2020) were searched for pepsin in saliva for LPR/GERD diagnosis. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the curve data were summarized to examine the accuracy. RESULTS: A total of 16 articles that included 2401 patients and 897 controls were analyzed. The pooled sensitivity and specificity for the diagnosis of GERD/LPR with Peptest were 62% (95% confidence interval [CI] 49%-73%) and 74% (95% CI 50%-90%), respectively. The summarized diagnostic odds ratio and area under the curve were 5.0 (95% CI 2-19) and 0.70 (95% CI 0.66-0.74), respectively. CONCLUSION: Peptest shows moderate diagnostic value for LPR and GERD. More studies with standard protocols should be done to verify its usefulness.


Assuntos
Refluxo Gastroesofágico/diagnóstico , Refluxo Laringofaríngeo/diagnóstico , Pepsina A/metabolismo , Saliva/metabolismo , Biomarcadores/metabolismo , Diagnóstico Diferencial , Refluxo Gastroesofágico/metabolismo , Humanos , Refluxo Laringofaríngeo/metabolismo , Curva ROC
4.
Molecules ; 26(12)2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34200590

RESUMO

The aim of the presented research was to obtain reconstituted atelocollagen fibers after extraction from poultry cartilage using the pepsin-acidic method in order to remove telopeptides from the tropocollagen. Firstly, we examined the extraction of collagen from the cartilage extracellular matrix (ECM) after proteoglycans (PG) had been removed by the action of salts, i.e., NaCl or chaotropic MgCl2. Additionally, the effects of the salt type used for PG and hyaluronic acid removal on the properties of self-assembled fibers in solutions at pH 7.4 and freeze-dried matrices were investigated. The basic features of the obtained fibers were characterized, including thermal properties using scanning calorimetry, rheological properties using dynamic oscillatory rheometry, and the structure by scanning electron microscopy. The fibers obtained after PG removal with both analyzed types of salts had similar thermal denaturation characteristics. However, the fibers after PG removal with NaCl, in contrast to those obtained after MgCl2 treatment, showed different rheological properties during gelatinization and smaller diameter size. Moreover, the degree of fibrillogenesis of collagens after NaCl treatment was complete compared to that with MgCl2, which was only partial (70%). The structures of fibers after lyophilization were fundamentally different. The matrices obtained after NaCl pretreatment form regular scaffolds in contrast to the thin, surface structures of the cartilage matrix after proteoglycans removal using MgCl2.


Assuntos
Cartilagem/metabolismo , Galinhas/metabolismo , Colágeno/metabolismo , Proteoglicanas/metabolismo , Cloreto de Sódio/metabolismo , Animais , Matriz Extracelular/metabolismo , Ácido Hialurônico/metabolismo , Pepsina A/metabolismo
5.
Food Chem ; 362: 130098, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34090041

RESUMO

The specificity of pepsin, the major protease of gastric digestion, has been previously investigated, but only regarding the primary sequence of the protein substrates. The present study aimed to consider in addition physicochemical and structural characteristics, at the molecular and sub-molecular scales. For six different proteins submitted to in vitro gastric digestion, the peptide bonds cleaved were determined from the peptides released and identified by LC-MS/MS. An original statistical approach, based on propensity scores calculated for each amino acid residue on both sides of the peptide bonds, concluded that preferential cleavage occurred after Leu and Phe, and before Ile. Moreover, reliable statistical models developed for predicting peptide bond cleavage, highlighted the predominant role of the amino acid residues at the N-terminal side of the peptide bonds, up to the seventh position (P7 and P7'). The significant influence of hydrophobicity, charge and structural constraints around the peptide bonds was also evidenced.


Assuntos
Pepsina A/metabolismo , Proteínas/metabolismo , Sequência de Aminoácidos , Aminoácidos , Cromatografia Líquida , Endopeptidases/metabolismo , Modelos Estatísticos , Peptídeos/metabolismo , Proteínas/química , Proteólise , Especificidade por Substrato , Espectrometria de Massas em Tandem
6.
Medicine (Baltimore) ; 100(20): e25787, 2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34011039

RESUMO

ABSTRACT: The aim of this study is to explore the relationship between gastroesophageal reflux disease (GERD) and vocal fold polyps (VFPs).This is a Case-Control study and was performed with the help of The Second Affiliated Hospital of Chongqing Medical University.Twenty-seven patients with VFP and 20 controls without VFP were recruited between May and October 2018. All the subjects underwent a saliva pepsin test, completed the GerdQ questionnaire and 24-hour multichannel intraluminal impedance with pH (24-h MII-pH) monitoring. Twenty-five resected VFP specimens were examined with immunohistochemical (IHC) and double immunofluorescence (IF) staining.The incidence of GERD in the VFP group was significantly higher than that in the control group (P = .003). Patients with VFP had significantly higher GerdQ scores, pepsin concentrations, and pepsin-positive rates (P < .05). Moreover, the number of proximal and upright reflux events was significantly higher in the VFP group (P < .05). The pepsin concentration in saliva showed a significant positive correlation with the pepsin levels in tissues (r2 = 0.50, P = .011). Pepsin and TGF-ß1-positive cells were colocalized with CD45RO-positive cells. IHC staining showed that the majority of VFP patients had a positive expression of pepsin (20/25, 80%) and pepsin-positive cells were found in both the squamous epithelium and mesenchymal tissues. IHC staining of TGF-ß1 in VFP revealed findings similar to those of pepsin staining.GERD is an important risk factor for VFP. Pepsin may promote the aggregation of immune cells, increase the local cytokines, and promote inflammatory reaction, suggesting a potential new pathogenesis for VFP. The saliva pepsin test is a reliable method for GERD diagnosis.


Assuntos
Refluxo Gastroesofágico/epidemiologia , Pólipos/epidemiologia , Mucosa Respiratória/patologia , Prega Vocal/patologia , Adulto , Idoso , Estudos de Casos e Controles , Monitoramento do pH Esofágico , Feminino , Refluxo Gastroesofágico/complicações , Refluxo Gastroesofágico/diagnóstico , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Pepsina A/análise , Pepsina A/metabolismo , Pólipos/etiologia , Pólipos/patologia , Pólipos/cirurgia , Estudos Prospectivos , Mucosa Respiratória/cirurgia , Fatores de Risco , Saliva/química , Prega Vocal/cirurgia
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 258: 119859, 2021 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-33957444

RESUMO

Naringenin and naringin are two natural compounds with important health benefits, whether as food or drug. It is necessary to study the interactions between naringenin/naringin and digestive proteases, such as trypsin and pepsin. In this study, the bindings of naringenin and naringin to trypsin and pepsin were investigated using multi-spectroscopy analysis and computational modeling approaches. Fluorescence experiments indicate that both naringenin and naringin can quench the intrinsic fluorescence of trypsin/pepsin via static quenching mechanism. Naringin binds trypsin/pepsin in a more firmly way than naringenin. Thermodynamic analysis reveals that the interactions of naringenin/naringin and trypsin/pepsin are synergistically driven by enthalpy and entropy, and the major driving forces are hydrophobic, electrostatic interactions and hydrogen bonding. Synchronous fluorescence spectroscopy, circular dichroism spectroscopy and FT-IR show that naringenin/naringin may induce microenvironmental and conformational changes of trypsin and pepsin. Molecular docking reveals that naringenin binds in the close vicinity of the active site (Ser-195) of trypsin and Asp-32 (the catalytic activity of pepsin) appears in naringin-pepsin system. The direct interactions between naringenin or naringin and catalytic amino acid residues will inhibit the catalytic activity of trypsin and pepsin, respectively. The results of molecular dynamic simulation validate the reliability of the docking results.


Assuntos
Pepsina A , Dicroísmo Circular , Flavanonas , Simulação de Acoplamento Molecular , Pepsina A/metabolismo , Ligação Proteica , Reprodutibilidade dos Testes , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de Fourier , Tripsina/metabolismo
8.
Food Chem ; 361: 130061, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34023689

RESUMO

Two collagens were made from giant salamander (Andrias davidianus) skin by using acid and pepsin extraction methods. The yields of acid-soluble and pepsin-soluble collagens were 26.9 and 58.7%, respectively. The results of spectrum, electrophoresis and amino acid analysis showed that they were type 1 collagen with two α and one ß peptides and high imino acid content. They had low solubility at a pH above 6 or salt concentration over 5%. The pepsin-soluble collagen had a better emulsion activity index. The odorants in raw skin and collagens were identified and evaluated using gas-chromatography mass-spectrometer and olfactometry methods and sensory analysis. The fishy and fatty off-odors in skin were not perceivable in the collagens. Sour, ammonia-like, and acrid off-odors were found in the collagens due to acid and enzymatic hydrolysis and protein degradation. The off-odor intensity of pepsin-soluble collagen was low. It could be considered a good and safe collagen material.


Assuntos
Aminoácidos/análise , Colágeno Tipo I/química , Urodelos/metabolismo , Ácidos , Animais , Colágeno Tipo I/isolamento & purificação , Colágeno Tipo I/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Concentração de Íons de Hidrogênio , Hidrólise , Iminoácidos/análise , Odorantes/análise , Olfatometria , Pepsina A/metabolismo , Proteólise , Pele/metabolismo , Microextração em Fase Sólida , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier
9.
Int J Mol Sci ; 22(8)2021 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33924087

RESUMO

Pepsin refluxate is considered a risk factor for laryngopharyngeal carcinogenesis. Non-acidic pepsin was previously linked to an inflammatory and tumorigenic effect on laryngopharyngeal cells in vitro. Yet there is no clear evidence of the pepsin-effect on a specific oncogenic pathway and the importance of pH in this process. We hypothesized that less acidic pepsin triggers the activation of a specific oncogenic factor and related-signalling pathway. To explore the pepsin-effect in vitro, we performed intermittent exposure of 15 min, once per day, for a 5-day period, of human hypopharyngeal primary cells (HCs) to pepsin (1 mg/mL), at a weakly acidic pH of 5.0, a slightly acidic pH of 6.0, and a neutral pH of 7.0. We have documented that the extracellular environment at pH 6.0, and particularly pH 7.0, vs. pH 5.0, promotes the pepsin-effect on HCs, causing increased internalized pepsin and cell viability, a pronounced activation of EGFR accompanied by NF-κB and STAT3 activation, and a significant upregulation of EGFR, AKT1, mTOR, IL1ß, TNF-α, RELA(p65), BCL-2, IL6 and STAT3. We herein provide new evidence of the pepsin-effect on oncogenic EGFR activation and its related-signaling pathway at neutral and slightly acidic pH in HCs, opening a window to further explore the prevention and therapeutic approach of laryngopharyngeal reflux disease.


Assuntos
Transformação Celular Neoplásica/metabolismo , Receptores ErbB/metabolismo , Concentração de Íons de Hidrogênio , Pepsina A/metabolismo , Transdução de Sinais , Sobrevivência Celular , Transformação Celular Neoplásica/genética , Células Cultivadas , Receptores ErbB/agonistas , Receptores ErbB/genética , Humanos , Hipofaringe/citologia , Hipofaringe/metabolismo , NF-kappa B/metabolismo , Pepsina A/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Fator de Transcrição STAT3/metabolismo
10.
Food Funct ; 12(7): 3246-3265, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33877248

RESUMO

In this study, ß-carotene loaded oil-in-water emulsions were stabilized by complex interfaces composed of propylene glycol alginate (PGA), rhamnolipids (Rha), and zein colloidal particles (ZCPs). The influence of mixed biopolymer-surfactant, biopolymer-particle, surfactant-particle and biopolymer-surfactant-particle interfaces on the performance of the emulsions was investigated. The stability, microstructure, rheological properties, and in vitro gastrointestinal digestion of the emulsions were controlled by regulating the adding sequence and mass ratio of the multiple stabilizers. The droplet size of the emulsion was in the range of 14-77 µm. After encapsulation into the emulsions stabilized by the complex interfaces, the photothermal stability of ß-carotene were increased by 41.53% and 21.52%, respectively. The co-existence of particles, biopolymers, and surfactants could induce competitive displacement, multilayer deposition and an interparticle network at the interface. Compared with a single PGA- or Rha-stabilized emulsion, the complex interface-stabilized emulsion reduced the release of FFA by 28.06% and 26.16%, respectively. The interfacial composition of the emulsion and the delayed lipid digestion further affected the bioaccessibility of ß-carotene in the gastrointestinal tract (GIT). The mixed biopolymer-particle-surfactant interface-stabilized emulsion could be incorporated in foods, pharmaceuticals and cosmetics for excellent stability, targeted nutrient delivery and controlled lipolysis.


Assuntos
Biopolímeros/química , Emulsões/química , Tensoativos/química , beta Caroteno/química , beta Caroteno/farmacocinética , Disponibilidade Biológica , Digestão , Estabilidade de Medicamentos , Elasticidade , Emulsões/metabolismo , Trato Gastrointestinal/metabolismo , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Pepsina A/metabolismo , Viscosidade , Zeína/química , beta Caroteno/administração & dosagem
11.
Anal Biochem ; 622: 114166, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-33726980

RESUMO

Novel food-derived anti cancerogenic bioactive peptides were characterized by goat milk pepsin hydrolysate. Pepsin treated casein fraction of goat milk caused an apoptotic cell death on the HCT116 cell lines. These bioactive peptides are encrypted in the protein structure in the inactive form and can become active during gastrointestinal digestion in the body. In this study, the possible therapeutic effect of goat milk-based bioactive peptides on human colorectal cancer cell lines was investigated. Goat milk-derived bioactive peptides were extracted from the casein and whey protein fractions using trypsin, pepsin, and papain enzymes. The bioactive peptides were characterized by the liquid chromatography quadrupole time of flight mass spectrometry. Both enzyme-treated casein and whey fractions were incubated with the HCT116 cell lines, and then the cell cytotoxicity was evaluated using MTT assay. The type of cell death was analyzed by flow cytometry using Annexin V and propidium iodide. Among all applications, the pepsin-treated casein fraction was the highest potential peptides that cause 80.92% apoptotic cell death. In conclusion, pepsin treated casein fraction exhibited antiproliferative activity against HCT116 cells. The bioactive peptides of this fraction can be considered as a potential source for the development of new anti cancerogenic agents.


Assuntos
Anticarcinógenos/farmacologia , Neoplasias Colorretais/patologia , Leite/química , Peptídeos/farmacologia , Animais , Anticarcinógenos/química , Apoptose/efeitos dos fármacos , Caseínas/química , Caseínas/metabolismo , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida/métodos , Neoplasias Colorretais/tratamento farmacológico , Citometria de Fluxo/métodos , Cabras , Células HCT116 , Humanos , Papaína/metabolismo , Pepsina A/metabolismo , Peptídeos/química , Espectrometria de Massas em Tandem/métodos , Tripsina/metabolismo
12.
J Dairy Sci ; 104(4): 3853-3862, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33551166

RESUMO

Osteoporosis is a common disease that frequently occurs in the older population, particularly in postmenopausal women. It severely compromises the health of the older population, and the drugs commonly used to treat osteoporosis have a variety of adverse effects. Lactoferrin (LF) is a protein present in milk that has recently been found to exhibit osteogenic activity. Lactoferrin is nontoxic and harmless, suggesting that it may have excellent biocompatibility and tolerability after human consumption. Oral consumption of LF in an ovariectomized rat model has been found to ameliorate osteoporosis. However, the mechanism underlying this effect remains to be clarified. In this study, bovine LF (bLF) was first hydrolyzed by pepsin for 1 h, and the hydrolyzed mixture was freeze-dried and collected. The hydrolyzed mixture was then separated into 5 components (E1-E5), of which E3 had the greatest effect in promoting proliferation of osteoblasts (MC3T3-E1). Component E3 was further isolated into 21 components with preparative reversed phase HPLC, and the E3-15 component had maximal bioactivity. With HPLC-mass spectrometry and peptide sequencing, E3-15 was identified to contain amino acids 97 to 208 from the bLF N terminus. Then, E3-15 was divided into 6 different peptide segments (P1-P6), and the corresponding segments were generated by solid-phase synthesis. Only the P1 peptide (amino acids 97-122 from the N terminus of bLF) significantly promoted osteoblast proliferation. The bioactivity of P1 toward osteoblast cells and alkaline phosphatase activity were tested as a function of P1 concentration, and a nonlinear effect was observed.


Assuntos
Lactoferrina , Pepsina A , Animais , Lactoferrina/metabolismo , Osteoblastos/metabolismo , Osteogênese , Pepsina A/metabolismo , Peptídeos , Ratos
13.
Food Funct ; 12(5): 2112-2125, 2021 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-33564805

RESUMO

Breakdown of solid foods during gastric digestion plays a major role in the release and absorption of nutrients in the gastrointestinal tract. The breakdown mechanisms of foods during gastric digestion may be influenced by composition, particle geometry, and the resulting moisture uptake and gastric emptying. The extent of breakdown may have implications on the pH, pepsin activity, and subsequent protein hydrolysis. This study aims to identify the influence of particle geometry on pH, buffering capacity, and breakdown mechanisms during in vitro dynamic gastric digestion. Whey protein gels made in different geometries (small, medium, and large cubes with side lengths of 3.1, 5.2, and 10.3 mm, respectively, and spheres with a diameter of 6.5 mm) were subjected to gastric digestion using the Human Gastric Simulator (HGS) over a 180 min period. Particle size in the bulk digesta showed the breakdown mechanism of spheres was primarily by erosion, whereas breakdown of cubes was by fragmentation at the beginning of digestion, followed by erosion. Moisture uptake and gastric emptying of dry matter were significantly influenced by digestion time, particle geometry, and their interaction (p < 0.001). Initial buffering capacity of the gels was highest in small cubes and lowest in large cubes, causing the pH to decrease faster in large cubes. There was a higher pepsin activity in the liquid phase of the digesta in large cubes compared to the rest of the treatments, which was hypothesized to be due to a diffusion limitation of pepsin, resulting in less diffusion into large cubes due to their lower total specific surface area. Further work is needed to develop quantitative connections between food initial properties, breakdown mechanisms, and their implications on pH, pepsin activity, and nutrient digestibility for future food design.


Assuntos
Digestão , Proteínas do Soro do Leite/metabolismo , Tampões (Química) , Esvaziamento Gástrico , Suco Gástrico/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Modelos Biológicos , Tamanho da Partícula , Pepsina A/metabolismo , Saliva/metabolismo , Água/metabolismo , Proteínas do Soro do Leite/química , alfa-Amilases/metabolismo
14.
J Food Sci ; 86(3): 1144-1152, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33580498

RESUMO

Major cashew allergen, Ana o 1, was purified in its native form from cashew seeds and subjected to enzymatic deglycosylation using PNGase F to assess the potential role of N-glycans in immunoreactivity. Western and dot blotting with pooled human plasma containing anticashew IgE revealed that deglycosylation increased IgE-binding of Ana o 1. Removal of N-glycans may have exposed previously masked Ana o 1 epitopes. Purified glycosylated and deglycosylated Ana o 1 were also subjected to in vitro pepsin digestion at pH 3.0 for 2 hr. Both glycosylated and deglycosylated Ana o 1 remained stable and reactive with IgE antibodies following digestion. PRACTICAL APPLICATION: Understanding the role of glycosylation in Ana o 1 immunoreactivity may provide insight into the potential development of hypoallergenic cashews/cashew products for sensitive individuals in the future.


Assuntos
Anacardium/química , Antígenos de Plantas/imunologia , Epitopos/imunologia , Imunoglobulina E/imunologia , Hipersensibilidade a Noz/imunologia , Pepsina A/metabolismo , Proteínas de Plantas/imunologia , Antígenos de Plantas/química , Glicosilação , Humanos , Imunoglobulina E/sangue , Proteínas de Plantas/química , Sementes/química
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 253: 119523, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33621938

RESUMO

Pepsin is an aspartic protease that is involved in the digestion of food in the stomach of mammals. Continuous and long-term use of therapeutic agents will cause chronic contact of the drug with pepsin, and as a result, the structure and function of enzyme may change. In this regard the interactions of isoniazid and rifampin as the first line treatments of tuberculosis with pepsin were investigated by various methods such as fluorescence spectroscopy, FTIR, molecular docking and molecular dynamics simulation. Based on the results obtained in this study, the mentioned drugs can form stable complexes with pepsin and the structure of protein changes slightly. According to the results, the major forces in the formation of the protein-drug complex are electrostatic and hydrophobic forces for isoniazid and rifampin respectively and isoniazid shows to form a stronger binding with protein. The FTIR spectrum of the protein shows that little change was occurred in the structure of pepsin in the presence of the drugs. Molecular modeling results of the binding of isoniazid and rifampin to the pepsin confirm laboratory results and show that the binding site of drugs is close to the active site of the enzyme. Also, the activity of pepsin in the presence of both drugs has significantly increased.


Assuntos
Isoniazida , Pepsina A , Animais , Simulação de Acoplamento Molecular , Pepsina A/metabolismo , Ligação Proteica , Rifampina
16.
Food Chem ; 350: 129188, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33588280

RESUMO

Hempseed meal after protein isolation (HM-PI) is a co-product obtained from hempseed. The objectives were to characterize and determine the effect of drying on HM-PI. HM-PI was produced using three drying methods: freeze (FD), vacuum oven (VOD), and oven drying (OD). HM-PI contained over 70% protein and had similar or higher level of essential amino acids than recommended values for human adults. Osborne fractionation indicated that glutelin was the most dominant fraction in HM-PI. FD HMPI has a significant lower surface hydrophobicity and higher in vitro protein digestibility than OD and VOD HM-PI. FD HM-PI demonstrated better functional properties than OD and VOD HM-PI. Pepsin-pancreatin digestion of VOD, FD and OD resulted in comparable and considerable antioxidant and anti-inflammatory properties. This is the first report on the characterization of HM-PI, a co-product of hempseed processing. HM-PI could serve as a novel food protein ingredient resulting in increase utilization of hempseed.


Assuntos
Cannabis/química , Fenômenos Químicos , Dessecação/métodos , Resinas Vegetais/química , Antioxidantes/análise , Liofilização , Humanos , Pancreatina/metabolismo , Pepsina A/metabolismo , Resinas Vegetais/isolamento & purificação , Resinas Vegetais/metabolismo
17.
Biomed Res Int ; 2021: 4721812, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33564676

RESUMO

Background: Elderly patients receiving nasal feeding have weaker physiological function, and placement of a nasogastric tube weakens the natural barrier of the cardia-esophageal sphincter; therefore, the risk of gastroesophageal reflux (GER) is higher. Many studies have shown that pepsin is extremely sensitive in predicting GERD, so this study intends to investigate the level of pepsin in saliva of elderly patients with nasal feeding and analyze its influencing factors. Methods: This was a cross-sectional study. Patients admitted to the Chinese PLA General Hospital from April 2018 to October 2018 who received nasal feeding were included. One ml of saliva was collected from each patient in while sitting during fasting in the morning and 1 hour after lunch for 3 consecutive days. Pepsin was quantified by enzyme-linked immunosorbent assay (ELISA). The patients were predivided into two groups (≥7.75µg/ml or <7.75µg/ml) based on the median pepsin. Baseline and clinical factors were compared. Results: The mean age of the patients was 91.09 ± 4.91 years. There were statistical differences in diabetes and feeding methods between the two groups. There was a positive correlation between the morning and postprandial pepsin levels (r = 0.442, P < 0.001), and has no statistical difference (P = 0.175). Multivariate analysis showed that the risk factors for higher pepsin levels were diabetes (odds ratio (OR): 2.67; 95% CI: 1.225-5.819, P = 0.013) and nasal feeding methods (OR: 2.475; 95% CI: 1.183-5.180, P=0.016). Conclusions: For patients undergoing nasal feeding who are older than 80 years, the fasting and 1-hour postprandial pepsin concentration were consistent. Diabetes and feeding methods are risk factors for high pepsin levels. For the elderly over 80 years old, age has no influence on pepsin concentration.


Assuntos
Refluxo Gastroesofágico/metabolismo , Pepsina A/metabolismo , Saliva/metabolismo , Administração Intranasal , Idoso , Idoso de 80 Anos ou mais , Ingestão de Alimentos , Impedância Elétrica , Monitoramento do pH Esofágico , Esôfago/metabolismo , Esôfago/fisiopatologia , Métodos de Alimentação , Feminino , Refluxo Gastroesofágico/fisiopatologia , Humanos , Masculino , Pepsina A/isolamento & purificação , Saliva/enzimologia
18.
Otolaryngol Head Neck Surg ; 164(1): 160-165, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32692278

RESUMO

OBJECTIVE: To measure pepsin expression in patients with vocal fold leukoplakia and elucidate its clinical significance. STUDY DESIGN: Retrospective analysis of pathologic archive specimens. SETTING: Affiliated university hospital. SUBJECTS AND METHODS: The study included 45 patients with vocal fold leukoplakia and 19 with vocal fold polyps who underwent surgical treatment between December 2013 and July 2016. Masses were detected on both vocal cords in 5 patients with vocal fold leukoplakia and in 1 patient with vocal fold polyps. Immunohistochemistry was used to assess pepsin expression. In addition, the relationship of pepsin expression level with clinical characteristics of vocal fold leukoplakia was assessed. RESULTS: The rate of pepsin expression was high in the polyp group (75%) and the leukoplakia group (68%); however, the difference between groups was not significant (P > .05). Pepsin expression significantly increased according to grade of dysplasia (mild, 57.1%; moderate, 88.9%; severe, 100.0%; P = .034). Similarly, the percentage of lesions that exhibited strongly positive pepsin expression increased with the grade of dysplasia (mild, 37.1%; moderate, 66.7%; severe, 100.0%; P = .005). The leukoplakia recurrence rate was higher in patients with positive pepsin expression than in patients with negative pepsin expression but without a significant difference (P > .05). CONCLUSION: Our study suggests that pepsin was associated with the grade of dysplasia of vocal cord leukoplakia. Further investigation with appropriate control groups and controlling for other risk factors, such as smoking or alcohol consumption, is needed.


Assuntos
Doenças da Laringe/metabolismo , Leucoplasia/metabolismo , Pepsina A/metabolismo , Pólipos/metabolismo , Lesões Pré-Cancerosas/metabolismo , Prega Vocal/metabolismo , Adulto , Idoso , Biomarcadores/metabolismo , Feminino , Humanos , Doenças da Laringe/patologia , Leucoplasia/patologia , Masculino , Pessoa de Meia-Idade , Pólipos/patologia , Lesões Pré-Cancerosas/patologia , Estudos Retrospectivos
19.
Laryngoscope ; 131(2): 350-359, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32510588

RESUMO

OBJECTIVES/HYPOTHESIS: To assess the impact of diet on the saliva pepsin concentration of patients with laryngopharyngeal reflux (LPR). STUDY DESIGN: Non-controlled Prospective Study. METHODS: Patients with positive LPR regarding hypopharyngeal-esophageal impedance-pH monitoring (HEMII-pH) were enrolled from three European Hospitals. Patients collected three saliva samples, respectively, in the morning (fasting), and 1 to 2 hour after lunch and dinner. Patients carefully detailed foods and beverages consumed during meals and before the pepsin samples. The 3-month treatment was based on the association of diet, proton pump inhibitors, alginate, or magaldrate regarding the HEMII-pH characteristics. Reflux Symptom Score (RSS) and Reflux Sign Assessment (RSA) were used for assessing the pre- to posttreatment clinical evolution. The Refluxogenic Diet Score and the Refluxogenic Score of a Dish (RESDI) were used to assess the refluxogenic potential of foods and beverages. The relationship between saliva pepsin concentration, HEMII-pH, RESDI, RSS, and RSA was investigated through multiple linear regression. RESULTS: Forty-two patients were included. The saliva pepsin concentration of the 24-hour period of testing was significantly associated with foods and beverages consumed during the testing period and the evening dinner (rs = 0.973, P < .001). RSS and RSA significantly improved throughout treatment. The level of saliva pepsin in the morning was a negative predictive factor of the therapeutic response regarding RSA and RSS (P < .036). CONCLUSIONS: Foods and beverages may significantly impact the saliva pepsin concentration of patients with LPR. Patients with high-level saliva pepsin in the morning had lower therapeutic response compared with those with low-level saliva pepsin. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:350-359, 2021.


Assuntos
Dieta/efeitos adversos , Refluxo Laringofaríngeo/metabolismo , Refeições/fisiologia , Pepsina A/metabolismo , Saliva/química , Adulto , Idoso , Dieta/estatística & dados numéricos , Inquéritos sobre Dietas , Impedância Elétrica , Monitoramento do pH Esofágico , Feminino , Humanos , Refluxo Laringofaríngeo/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Inibidores da Bomba de Prótons/uso terapêutico , Índice de Gravidade de Doença , Adulto Jovem
20.
Food Chem ; 343: 128461, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33131957

RESUMO

Silkworm pupae are edible insects with high-quality nutrition in many Asian countries, but consumption of silkworm pupae can cause severe IgE-mediated allergic disease. The aim of this study was to investigate the effect of heat, enzymatic hydrolysis and acid-alkali treatment on the allergenicity of silkworm pupa protein extract (SPPE). Heating reduced the allergenicity of SPPE when the temperature was higher than 60 °C. Spectroscopy studies suggested an unfolded conformation of SPPE with heating, dependent on temperature and time. Enzymatic hydrolysis revealed that SPPE at 25 to 33 kDa contained pepsin- and trypsin-resistant allergens. The results of acid-alkali treatment suggested that low pH can promote hydrolysis of SPPE and decrease its allergenicity. Thus, heat, enzymatic hydrolysis and acid-alkali treatment can significantly decrease the allergenicity of SPPE, with heat-, enzyme- and acid-alkali-resistant allergens at 25 to 33 kDa SPPE. This study can help in the development of methods to prepare silkworm pupa protein.


Assuntos
Alérgenos/imunologia , Insetos Comestíveis/química , Proteínas de Insetos/química , Proteínas de Insetos/imunologia , Alérgenos/química , Animais , Ásia , Bombyx/química , Digestão , Insetos Comestíveis/imunologia , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Histamina/metabolismo , Temperatura Alta , Humanos , Hidrólise , Hipersensibilidade/etiologia , Proteínas de Insetos/efeitos adversos , Proteínas de Insetos/metabolismo , Pepsina A/metabolismo , Pupa/química , Tripsina/metabolismo
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