The main objective of this work was to characterize the acid‐soluble collagen (ASC) and pepsin‐soluble collagen (PSC) from the body wall of the sea cucumber scientifically called, Stichopus hermanni. ...For the extraction of ASC and PSC, the pre‐treated sea cucumber body walls were subjected to 0.5 M acetic acid and 5 g L−1 pepsin, respectively. The yield of ASC (7.30% ± 0.30%) was found to be lower than the PSC (23.66% ± 0.15%), despite both ASC and PSC having similar chemical compositions except for the quantity of protein. The collagens produced from ASC and PSC show maximum peaks on ultraviolet–visible spectroscopic profiles at wavelengths of 230 and 235 nm, respectively, with no significant difference in the maximum temperature (Tmax) of the extracted ASC and PSC. The ASC's coloration was whiter than that of the PSC. As a result, the collagen obtained from the body wall of the sea cucumber showed promise for usage as a substitute for collagen derived from marine sources.
Practical Application
The two most popular methods of collagen extraction were acid hydrolysis and enzymatic hydrolysis. To determine whether the extracted collagen is a suitable substitute for animal collagen in different industries, it is required to characterize its physicochemical qualities. This study discovered a new application for marine collagen in the food industry: The sea cucumber has collagen with a greater yield in pepsin extraction with good physicochemical qualities.
► Antioxidant hydrolysates from walnut proteins were prepared using neutrase, alcalase and pepsin. ► Walnut protein hydrolysates were purified sequentially by ultrafiltration, gel filtration and ...RP-HPLC. ► The activities of peptide were evaluated by radicals scavenging, reducing power and lipid peroxidation inhibitory activity. ► The structure of purified peptide was determined as Ala-Asp-Ala-Phe.
Walnut proteins were hydrolyzed separately using three different proteases to obtain antioxidant peptides. The antioxidant activities of the hydrolysates were measured using 1,1-diphenyl-2-picryl hydrazyl (DPPH) assay. Among hydrolysates, pepsin hydrolysate obtained by 3h exhibited the highest antioxidant activities, which could also quench the hydroxyl radical, chelate ferrous ion, exhibit reducing power and inhibit the lipid peroxidation. Then, 3-h pepsin hydrolysates were purified sequentially by ultrafiltration, gel filtration and RP-HPLC. The sequence of the peptide with the highest antioxidative activity was identified to be Ala-Asp-Ala-Phe (423.23Da) using RP-HPLC-ESI-MS, which was identified for the first time from walnut protein hydrolysates. Last, the inhibition of the peptide on lipid peroxidation was similar with that of reduced glutathione (GSH). These results indicate that the protein hydrolysates and/or its isolated peptides may be effectively used as food additives.
Objective Laryngopharyngeal reflux (LPR) is a common illness of otolaryngology visits. Over the past few years, pepsin has become a promising marker of LPR. The objective of the present research is ...to analyze the existing literature using pepsin as a diagnostic tool of LPR through a systematic review. Data Sources PubMed (Medline), Trip Database, Cochrane Library, EMBASE, SUMsearch, and Web of Science. Review Methods The outcome assessed was the presence of pepsin in LPR patients. We included articles in which pepsin was studied in LPR patients (clinically suspected or with confirmed diagnosis). Studies with no control group, comparison group, and/or a sample size lower than 20 patients were excluded. Results Twelve studies were included. All included studies, with the exception of 2, found statistically significant differences for pepsin in cases compared with healthy controls. Conclusion Pepsin might be a reliable marker in LPR patients, although questions remain about optimal timing, location, nature, and threshold values for pepsin testing. Future investigations are necessary to clarify the best method to use pepsin in the diagnostic process of LPR.
•Isothermal titration calorimetry is feasible for studying protein hydrolysis kinetics.•The enzymatic kinetics of pepsin with bovine serum albumin has been quantified.•Pepsin kinetics is influenced ...by both pH and ionic strength.•Pepsin is more efficient to intact proteins than to intermediate peptides.
Pepsin is the first protease that food proteins encounter in the digestive tract. However, most of the previous studies on the enzymatic kinetics of pepsin were based on the hydrolysis of small synthetic peptides, due to the limitations in methodology and the complexity of protein substrate. To better understand the role of pepsin in protein digestion, we used isothermal titration calorimetry to study the enzymatic kinetics of pepsin with bovine serum albumin as the substrate. We found that pepsin has a higher catalytic rate at lower pH, while its affinity to substrate is lower. At the same pH, pepsin has lower activity and affinity at higher ionic strengths. We found contrasting kinetic parameters for pepsin-catalyzed hydrolysis of bovine serum albumin and of small synthetic peptides. Time-dependent kinetics also showed that pepsin has lower efficiency towards intermediate peptides during hydrolysis.
The number of therapeutic monoclonal antibodies (mAbs) is growing rapidly due to their widespread use for treating various diseases and health conditions. Assessing the glycosylation profile of mAbs ...during production is essential to ensuring their safety and efficacy. This research aims to rapidly isolate and digest mAbs for liquid chromatography–tandem mass spectrometry (LC–MS/MS) identification of glycans and monitoring of glycosylation patterns, potentially during manufacturing. Immobilization of an Fc region-specific ligand, oFc20, in a porous membrane enables the enrichment of mAbs from cell culture supernatant and efficient elution with an acidic solution. Subsequent digestion of the mAb eluate occurred in a pepsin-modified membrane within 5 min. The procedure does not require alkylation and desalting, greatly shortening the sample preparation time. Subsequent LC–MS/MS analysis identified 11 major mAb N-glycan proteoforms and assessed the relative peak areas of the glycosylated peptides. This approach is suitable for the glycosylation profiling of various human IgG mAbs, including biosimilars and different IgG subclasses. The total time required for this workflow is less than 2 h, whereas the conventional enzymatic release and labeling of glycans can take much longer. Thus, the integrated membranes are suitable for facilitating the analysis of mAb glycosylation patterns.
To evaluate the necessity of multiple salivary pepsin tests within a day when diagnosing laryngopharyngeal reflux.
Prospective cohort study.
Tertiary hospitals.
A total of 138 patients with signs ...and/or symptoms associated with laryngopharyngeal reflux were included. Salivary pepsin was detected on the day of 24-hour pH monitoring, and the results of salivary pepsin detected once in the morning and multiple times in 1 day were compared with the results of pH monitoring.
Among the 138 patients, pH monitoring results were positive in 112. Salivary pepsin was positive in 47 cases in the morning, which was not consistent with the results of pH monitoring (kappa value = 0.117). With the pH monitoring results as the standard, the salivary pepsin detected once in the morning had a sensitivity of 38.4% (43/112) and a specificity of 84.6% (22/26) for the diagnosis of laryngopharyngeal reflux. When salivary pepsin was detected multiple times per day, 102 patients tested positive. The consistency with pH monitoring was moderate (kappa value = 0.587). The sensitivity was 86.6% (97/112), and the specificity was 80.8% (21/26). Of the 97 patients with positive results from pH monitoring and salivary pepsin detected multiple times a day, 54 had negative findings for a single detection in the morning, indicating that 55.7% (54/97) of the true positive cases were missed.
Although a single detection of salivary pepsin in the morning is more economical, the sensitivity is too low, and it is necessary to detect it multiple times a day.
The interaction of pepsin with sunset yellow food additive (SY) was studied by fluorescence spectroscopy and molecular dynamics simulation. The experimental results indicated that SY can quench the ...fluorescence of pepsin with static quenching. The apparent binding constant Ka and binding site number n were evaluated at different temperatures. Thermodynamic analysis suggests that SY interact with pepsin spontaneously by van der Waal's forces and hydrogen bond formation. Three-dimensional fluorescence spectra showed that pepsin undergoes a slightly conformation change when it interacts with SY. The molecular dynamics simulation (MD) revealed that the binding site is located mainly on the tyrosine residues at the entrance of the active site of pepsin and the main interactions occurred between SY and pepsin are hydrogen bond and stacking interactions, according to experimental results. Furthermore, the binding between SY and pepsin can inhibit pepsin activity. Our MD results showed that the SY prevents substrate from entering the active site by making a barrier at the entrance of the active site, reducing the pepsin activity.
•Sunset yellow quenched the fluorescence of pepsin.•Sunset yellow interacts with pepsin by van der Waal's forces and hydrogen bonds.•Pepsin undergoes a conformation change when it interacts with sunset yellow.•Sunset yellow can inhibit pepsin activity.•Sunset yellow prevents substrate from entering the active site.
Solubilized, gel-forming decellularized extracellular matrix (dECM) is used in a wide range of basic and translational research and due to its inherent bioactivity can promote structural and ...functional tissue remodeling. The animal-derived protease pepsin has become the standard proteolytic enzyme for the solubilization of almost all types of collagen-based dECM. In this study, pepsin was compared with papain, α-amylase, and collagenase for their potential to solubilize porcine liver dECM. Maximum preservation of bioactive components and native dECM properties was used as a decisive criterion for further application of the enzymes, with emphasis on minimal destruction of the protein structure and maintained capacity for physical thermogelation at neutral pH. The solubilized dECM digests, and/or their physically gelled hydrogels were characterized for their rheological properties, gelation kinetics, GAG content, proteomic composition, and growth factor profile. This study highlights papain as a plant-derived enzyme that can serve as a cost-effective alternative to animal-derived pepsin for the efficient solubilization of dECM. The resulting homogeneous papain-digested dECM preserved its thermally triggered gelation properties similar to pepsin digests, and the corresponding dECM hydrogels demonstrated their enhanced bioadhesiveness in single-cell force spectroscopy experiments with fibroblasts. The viability and proliferation of human HepaRG cells on dECM gels were similar to those on pure rat tail collagen type I gels. Papain is not only highly effective and economically attractive for dECM solubilization but also particularly interesting when digesting human-tissue-derived dECM for regenerative applications, where animal-derived materials are to be avoided.
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
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•The interaction of apigenin to pepsin were revealed by spectroscopy, molecular docking.•Apigenin performed static quenching of pepsin, and the interaction was spontaneous.•An impact ...of pepsin on the antioxidant activity of apigenin was checked.•The binding of apigenin to pepsin affected the microenvironment and structure of pepsin.
Pepsin plays an important role in nutrient metabolism. Apigenin (AP) is a beneficial polyphenol to human health. To enhance the bioavailability of AP and elucidate the inhibitory effect of AP on pepsin, the interaction mechanism of AP with pepsin was investigated using spectroscopic analysis and molecular docking, and the activity of pepsin and antioxidant activity of AP was also evaluated. Specifically, AP performed static quenching of pepsin and had only one binding site on pepsin. More interestingly, the interaction between AP and pepsin was spontaneous, while hydrogen bonds and van der Waals forces were the main binding forces. Generally, synchronous and three-dimensional fluorescence confirmed that AP induced the conformational changes of pepsin, and molecular docking proved the above results and illustrated the specific binding patterns. Specifically, AP inhibited the activity of pepsin, while pepsin decreased the antioxidant activity of AP. These results provided useful information for elucidating the interactions between AP and pepsin.
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