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Neurogastroenterology and Motility Feb 2012Pepsin has been proposed as a biomarker of reflux-related lung disease. The goal of this study was to determine (i) if there is a higher reflux burden as measured by...
BACKGROUND
Pepsin has been proposed as a biomarker of reflux-related lung disease. The goal of this study was to determine (i) if there is a higher reflux burden as measured by pH-MII in patients that are pepsin positive in the lung, and (ii) the sensitivity of pepsin in predicting pathologic reflux by pH, MII, and EGD.
METHODS
We recruited children between the ages of 1-21 with chronic cough or asthma undergoing bronchoscopy, esophagogastroduodenoscopy (EGD), and multichannel intraluminal impedance (pH-MII) probe placement. The reflux profiles were compared between those patients who were pepsin positive and negative; proportions were compared using Chi-squared analyses and means were compared using t-testing.
KEY RESULTS
Only the mean number of non-acid reflux events was associated with pepsin positivity (0.04). The sensitivity and specificity of pepsin in predicting pathologic reflux by pH-MII or EGD was 57% and 65%, respectively. The positive predictive value of pepsin in predicting pathologic reflux by pH, MII or EGD was 50% (11/22), and the negative predictive value was 71% (20/28). There was a significantly higher mean LLMI in patients who were pepsin positive compared with pepsin negative patients (81 ± 54 vs 47 ± 26, P = 0.001).
CONCLUSIONS & INFERENCES
Lung pepsin cannot predict pathologic reflux in the esophagus, but its correlation with lung inflammation suggests that pepsin may be an important biomarker for reflux-related lung disease.
Topics: Adolescent; Child; Child, Preschool; Esophageal pH Monitoring; Female; Gastroesophageal Reflux; Humans; Infant; Lung; Male; Pepsin A; Predictive Value of Tests; Sensitivity and Specificity; Young Adult
PubMed: 22141343
DOI: 10.1111/j.1365-2982.2011.01826.x -
Marine Drugs Oct 2022In search of alternative and sustainable sources of collagenous materials for biomedical applications, the scales of five Mediterranean fish species-fished in high...
Valorization of Fish Waste: Isolation and Characterization of Acid- and Pepsin-Soluble Collagen from the Scales of Mediterranean Fish and Fabrication of Collagen-Based Nanofibrous Scaffolds.
In search of alternative and sustainable sources of collagenous materials for biomedical applications, the scales of five Mediterranean fish species-fished in high tonnage in the Mediterranean region since they represent popular choices for the local diet-as well as those of the Atlantic salmon for comparison purposes, were comparatively studied for their acid- and pepsin-soluble collagen content. Fish scales that currently represent a discarded biomass of no value could be efficiently exploited for the production of a high added-value biomaterial. The isolated collagenous materials, which showed the typical electrophoretic patterns of type I collagen, were morphologically and physicochemically characterized. Using scanning electron microscopy the fibrous morphology of the isolated collagens was confirmed, while the hydroxyproline content, in conjunction with infrared spectroscopy and X-ray diffraction studies verified the characteristic for collagen amino acid profile and its secondary structure. The acid- and pepsin-soluble collagens isolated from the fish scales were blended with the bioactive sulfated marine polysaccharide ulvan and polyethylene oxide and electrospun to afford nanofibrous scaffolds that could find applications in the biomedical sector.
Topics: Animals; Pepsin A; Nanofibers; Collagen; Collagen Type I; Acids
PubMed: 36354987
DOI: 10.3390/md20110664 -
European Journal of Biochemistry Mar 19751. A cyclic hexapeptide, cyclo(-Gly2-Phe2-Gly-Lys-), and the corresponding open-chain hexapeptides, Gly2-Phe2-Gly-Lys and Phe-Gly-Lys-Gly2-Phe, have been synthesized and...
1. A cyclic hexapeptide, cyclo(-Gly2-Phe2-Gly-Lys-), and the corresponding open-chain hexapeptides, Gly2-Phe2-Gly-Lys and Phe-Gly-Lys-Gly2-Phe, have been synthesized and their susceptibilities to the hydrolytic action of pepsin and trypsin were determined. 2. The cyclic peptide was hydrolyzed slowly by trypsin to a hexapeptide Gly2-Phe2-Gly-Lys, the value of the Michaelis constant for this reaction being Km equals 0.00022 M. 3. The cyclic peptide was not cleaved by pepsin at all, but Gly2-Phe2-Gly-Lys was hydrolyzed rapidly at a Phe-Phe bond; Km equals 0.0091 M. 4. The cyclic peptide inhibits the hydrolysis of Gly2-Phe2-Gly-Lys by pepsin in a linear non-competitive manner, the value of the inhibition constant being Ki equals 0.004 M.
Topics: Hydrogen-Ion Concentration; Kinetics; Lysine; Oligopeptides; Pepsin A; Peptides, Cyclic; Phenylalanine; Trypsin
PubMed: 240680
DOI: 10.1111/j.1432-1033.1975.tb03995.x -
The Biochemical Journal May 19731. Evidence is given for the presence of at least five pepsinogens in a crude extract of mixed chicken stomachs. One of these was purified and could be activated to...
1. Evidence is given for the presence of at least five pepsinogens in a crude extract of mixed chicken stomachs. One of these was purified and could be activated to yield a single pepsin. 2. The molecular weights of the pepsinogen and pepsin were 36000 and 34000 respectively. The pepsin associated at low pH values and low ionic strength. 3. The amino acid analyses of both proteins are given. The pepsin was devoid of phosphate but contained carbohydrate. 4. The N-terminal amino acids of pepsinogen and pepsin were serine and threonine respectively. Five amino acids were released by carboxypeptidase A and it was deduced that serine may be the C-terminal one. 5. Each protein contained one thiol group per molecule as determined by titration with p-chloromercuribenzoate. The rate of the reaction was very rapid with pepsin, but much slower with pepsinogen, although the same group appeared to react in both instances. The enzymic activity of pepsin was unaffected by the modification. 6. The isoionic point of the pepsin was close to pH4.0 and the enzyme was stable for long periods at pH values up to 7.0. 7. The enzyme hydrolysed bisphenyl sulphite almost as rapidly as did pig pepsin A.
Topics: Amino Acids; Animals; Chickens; Chloromercuribenzoates; Chromatography, DEAE-Cellulose; Chromatography, Gel; Dialysis; Electrophoresis; Enzyme Activation; Galactosamine; Hydrogen-Ion Concentration; Molecular Weight; Pepsin A; Pepsinogens; Polysaccharides; Proventriculus; Species Specificity; Spectrophotometry; Spectrophotometry, Ultraviolet; Sulfhydryl Compounds; Ultracentrifugation
PubMed: 4578760
DOI: 10.1042/bj1330105 -
Microbial Cell Factories Sep 2022Due to the detrimental effects of chemical preservatives, there has been an increasing demand for safer, healthier and natural bio-preservatives. Bacteriocins have...
BACKGROUND
Due to the detrimental effects of chemical preservatives, there has been an increasing demand for safer, healthier and natural bio-preservatives. Bacteriocins have attracted increasing interest because of their potential as natural bio-preservatives.
RESULTS
We screened a large number of Bacillus thuringiensis strains and isolated one strain (B. thuringiensis P86) with antimicrobial activity against several foodborne pathogens. Three novel leaderless bacteriocins, including thucin A1, thucin A2 and thucin A3, were purified and identified from the culture supernatant of B. thuringiensis P86, whose molecular masses were 5552.02, 5578.07 and 5609.06 Da, respectively. Thucin A1 was then selected as a representative to be tested, and it exhibited potent inhibitory activity against all tested gram-positive bacteria. More importantly, thucin A1 showed stronger antimicrobial activity than nisin A against two important foodborne pathogens Bacillus cereus and Listeria monocytogenes. In addition, thucin A1 exhibited strong acid-base adaptability (pH 2-11), high endurance to heat, good stability to trypsin and pepsin, no hemolysis activity and cytotoxicity, and could effectively inhibit or eliminate Bacillus cereus and Listeria monocytogenes in skim milk.
CONCLUSIONS
Our findings indicate that these novel leaderless bacteriocins are potentially promising food biopreservatives.
Topics: Anti-Infective Agents; Bacillus cereus; Bacteriocins; Gram-Positive Bacteria; Listeria monocytogenes; Microbial Sensitivity Tests; Pepsin A; Trypsin
PubMed: 36123739
DOI: 10.1186/s12934-022-01912-3 -
Microbiology Spectrum Aug 2022Acid tolerance is an important feature of probiotic development. It is one of the factors underlying the beneficial effects of probiotics in the intestine. However, the...
Acid tolerance is an important feature of probiotic development. It is one of the factors underlying the beneficial effects of probiotics in the intestine. However, the methods used by different researchers to test acid tolerance vary, causing confusion in the interpretation of the results. Therefore, in this study, we determine the optimal conditions for the acid tolerance test using response surface methodology. The factors of pH (2.5 to 3.5), exposure time (1 to 2 h), and pepsin (presence or absence) were used as independent variables, and the survival rates of seven strains (Lacticaseibacillus casei KACC 12413, Lactiplantibacillus plantarum KACC 15357, Limosilactobacillus fermentum KACC 11441, WCFS1, Lacticaseibacillus rhamnosus GG, KCTC 21024, and WiKim 0112) known to have probiotic properties were used as dependent variables. The results of the analysis of variance (ANOVA) indicated that the pH value and exposure time in acidic environments significantly affected the acid tolerance test model, and their interaction also had an effect ( < 0.05). Using the ANOVA results, the condition of the acid tolerance test was optimized with a target of an 85% survival rate for each strain. The optimized conditions of the acid tolerance test were as follows: pH 2.92, exposure time of 1.73 h, and presence of pepsin and pH 3, exposure time of 1.98 h, and absence of pepsin. These results can optimize strain selection with rigorous acid tolerance without confusion by unifying the conditions for the acid tolerance test. The acid tolerance test, which is the first step in selecting probiotics, is not standardized and can often cause confusion in the interpretation of results. Thus, in the present study, we optimized the conditions for the acid tolerance test using response surface methodology. These optimized conditions can be used to screen for strains with acid tolerance.
Topics: Intestines; Lactobacillaceae; Lactobacillus plantarum; Pepsin A; Probiotics
PubMed: 35876583
DOI: 10.1128/spectrum.01625-22 -
Molecular & Cellular Proteomics : MCP Oct 2014Disulfide bond identification is important for a detailed understanding of protein structures, which directly affect their biological functions. Here we describe an...
Facilitating protein disulfide mapping by a combination of pepsin digestion, electron transfer higher energy dissociation (EThcD), and a dedicated search algorithm SlinkS.
Disulfide bond identification is important for a detailed understanding of protein structures, which directly affect their biological functions. Here we describe an integrated workflow for the fast and accurate identification of authentic protein disulfide bridges. This novel workflow incorporates acidic proteolytic digestion using pepsin to eliminate undesirable disulfide reshuffling during sample preparation and a novel search engine, SlinkS, to directly identify disulfide-bridged peptides isolated via electron transfer higher energy dissociation (EThcD). In EThcD fragmentation of disulfide-bridged peptides, electron transfer dissociation preferentially leads to the cleavage of the S-S bonds, generating two intense disulfide-cleaved peptides as primary fragment ions. Subsequently, higher energy collision dissociation primarily targets unreacted and charge-reduced precursor ions, inducing peptide backbone fragmentation. SlinkS is able to provide the accurate monoisotopic precursor masses of the two disulfide-cleaved peptides and the sequence of each linked peptide by matching the remaining EThcD product ions against a linear peptide database. The workflow was validated using a protein mixture containing six proteins rich in natural disulfide bridges. Using this pepsin-based workflow, we were able to efficiently and confidently identify a total of 31 unique Cys-Cys bonds (out of 43 disulfide bridges present), with no disulfide reshuffling products detected. Pepsin digestion not only outperformed trypsin digestion in terms of the number of detected authentic Cys-Cys bonds, but, more important, prevented the formation of artificially reshuffled disulfide bridges due to protein digestion under neutral pH. Our new workflow therefore provides a precise and generic approach for disulfide bridge mapping, which can be used to study protein folding, structure, and stability.
Topics: Algorithms; Disulfides; Electron Transport; Mass Spectrometry; Pepsin A; Peptide Mapping; Proteins; User-Computer Interface
PubMed: 24980484
DOI: 10.1074/mcp.O114.039057 -
Acta Medica Iranica Mar 2016Noise is considered as one of the most severe sources of environmental and workplace constraints. Many noise effects are well known on immune function, hormonal levels,...
Noise is considered as one of the most severe sources of environmental and workplace constraints. Many noise effects are well known on immune function, hormonal levels, cardiovascular and respiratory systems. In this study, our aim is to evaluate the effects of traffic noise exposure on basal and stimulated gastric pepsin secretion. 48 male rats were exposed to traffic noise (86 dB) for a short term of (8h/day for 1 day) and a long term of (8h/day for 7, 14, 21 and 28 days) as well as a control group. The gastric contents were collected by the wash-out technique. Pepsin secretion was measured by employing the Anson method. Histological studies were carried out on the epithelial layer. The corticosteroid hormone was measured in the serum for the stress augmentation. The present finding indicated no changes in pepsin secretion content in the short term, but in the 14 and 21 days traffic noise exposure, basal gastric pepsin secretion increased markedly compared to the control group. Histological results showed that the number of oxyntic glands and cell nuclei decreased in comparison with the control group while the thickness of the epithelial layer increases. In addition, the corticosterone levels increase in all groups in comparison with the control. It seems that the increase of gastric pepsin secretion is due to the description and translation processes in the peptic cells and needs enough time for completion.
Topics: Animals; Gastric Mucosa; Male; Noise; Pepsin A; Rats; Rats, Wistar
PubMed: 27107524
DOI: No ID Found -
Interaction Behavior Between Niclosamide and Pepsin Determined by Spectroscopic and Docking Methods.Journal of Fluorescence Nov 2015The interaction between niclosamide (NIC) and pepsin was investigated using multispectroscopic and molecular docking methods. Binding constant, number of binding sites,...
The interaction between niclosamide (NIC) and pepsin was investigated using multispectroscopic and molecular docking methods. Binding constant, number of binding sites, and thermodynamic parameters at different temperatures were measured. Results of fluorescence quenching and synchronous fluorescence spectroscopy in combination with three-dimensional fluorescence spectroscopy showed that changes occurred in the microenvironment of tryptophan residues and the molecular conformation of pepsin. Molecular interaction distance and energy-transfer efficiency between pepsin and NIC were determined based on Förster nonradiative energy-transfer mechanism. Furthermore, the binding of NIC inhibited pepsin activity in vitro. All these results indicated that NIC bound to pepsin mainly through hydrophobic interactions and hydrogen bonds at a single binding site. In conclusion, this study provided substantial molecular-level evidence that NIC could induce changes in pepsin structure and conformation.
Topics: Animals; Molecular Docking Simulation; Niclosamide; Pepsin A; Protein Binding; Protein Conformation; Salts; Spectrometry, Fluorescence; Swine
PubMed: 26410777
DOI: 10.1007/s10895-015-1655-5 -
Journal of Dairy Science Apr 2021Osteoporosis is a common disease that frequently occurs in the older population, particularly in postmenopausal women. It severely compromises the health of the older...
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.
Topics: Animals; Lactoferrin; Osteoblasts; Osteogenesis; Pepsin A; Peptides; Rats
PubMed: 33551166
DOI: 10.3168/jds.2020-19138