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Infant Nutrition: The First Two Years
Published in Fima Lifshitz, Childhood Nutrition, 2020
Arturo R. Hervada, Maria Hervada-Page
Finally, the ability to produce pancreatic amylase, an important enzyme in the digestion of complex carbohydrates, is not fully developed until nine months of life.9 Therefore, starches do not appear to be appropriate as the first food to initiate. Solid foods like fruits, with their simpler sugars, would seem to be more physiologic. The same can be said regarding the development of gastric pepsin.
Macromolecular Absorption From The Digestive Tract In Young Vertebrates
Published in Károly Baintner, Intestinal Absorption of Macromolecules and Immune Transmission from Mother to Young, 2019
Besides splitting the Met-Phe bond, chymosin has a ‘‘general proteolytic activity.” This is much slower than that of pepsin, but its pH optimum is higher, approximately pH 3.0 to 3.5.1448 Chymosin is widely used in cheese production, and may have been the first enzyme used in the industry.
The digestive system
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
Protein digestion begins in the stomach by the action of the gastric enzyme, pepsin. This enzyme fragments large protein molecules into smaller peptide chains. Digestion is continued in the small intestine by the pancreatic enzymes, trypsin, chymotrypsin, and carboxypeptidase. Similar to pepsin (pepsinogen), these enzymes are secreted as inactive precursors (trypsinogen, chymotrypsinogen and procarboxypeptidase). The intestinal enzyme enterokinase activates trypsin at the brush border. Trypsin then activates chymotrypsin and carboxypeptidase. These pancreatic enzymes hydrolyze the peptide chains into amino acids (40%), as well as dipeptides and tripeptides (60% combined).
Inflammation and Dry Eye-like Symptoms as Concomitant Manifestations of Laryngo-Pharyngeal Reflux
Published in Current Eye Research, 2023
Stefano Bonini, Antonio Di Zazzo, Pier Luigi Surico, Bijorn Omar Balzamino, Vitaliana Luccarelli, Matteo Niutta, Marco Coassin, Alessandra Micera
Pepsin, a typical biomarker of gastroesophageal reflux, was present in the tears of 51% of the LPR patients while only a small amount was detectable in healthy subjects. This finding parallels the results obtained by other investigators while previous reports indicated the presence of pepsin in the tears of 20% of patients with GERD.11,17 Pepsin is a proteolytic enzyme active at acidic pH. It plays a major role in the development of esophageal, pharyngeal, laryngeal, and nasal chronic mucosal inflammation.18 Several studies reported a pepsin salivary detection rate from 63% to 78% in patients with LPR, suggesting this test as additional support to the clinical diagnosis of LPR.19 The presence of pepsin in tears suggests the possibility of functional activity of this enzyme on the ocular surface, even in the presence of the neutral tear pH of healthy eyes.20 Alginates are typically used to protect the esophageal, gastric, and laryngopharyngeal mucosa from acidic reflux events and to counteract the effects of pepsin.21 In a preliminary study performed without controls, topical and systemic alginate treatments improved the signs and symptoms of dry eyes when concomitantly used with topical eye drops.22
Recent advances in proteolytic stability for peptide, protein, and antibody drug discovery
Published in Expert Opinion on Drug Discovery, 2021
Xianyin Lai, Jason Tang, Mohamed E.H. ElSayed
The stomach secretes a mixture of compounds, including water, mucus, hydrochloric acid, pepsin, and intrinsic factors. Among them, pepsin is the principal enzyme involved in peptide, protein, and antibody digestion, generating smaller peptides and amino acids [52]. Pepsin is an endopeptidase that breaks down peptide bonds within a polypeptide sequence through aspartic catalysis mechanism at a low pH (1.5–2.0) [53]. The proteolytic stabilities of the bovine serum albumin, ovomucoid, β-lactoglobulin A, β-lactoglobulin B, and lysozyme were evaluated with 3.2 mg/mL pepsin in simulated gastric fluids prepared as described in the United States Pharmacopoeia. Bovine serum albumin and ovomucoid were observed to be rapidly digested within 0.25 min at the beginning of the incubation time. Lysozyme was completely degraded in 30 min. β-lactoglobulin A and β-lactoglobulin B had degradation percentages of 34.3% and 17.2% after 60 min of incubation [51].
Narrow-band imaging combined with salivary pepsin to diagnose patients with laryngopharyngeal reflux
Published in Acta Oto-Laryngologica, 2021
Pepsin is a proteolytic enzyme whose precursor pepsinogen is produced only in the stomach. Therefore, an increased pepsin level in the saliva is considered a specific biomarker for gastric reflux or LPR. Detecting salivary pepsin using the fibrinogen digestion method, western blot analysis, and enzyme-linked immunosorbent assay (ELISA) is considered to be convenient and non-invasive [4]. Given the non-invasive nature of this test, it was considered to be a useful method in the diagnosis of gastroesophageal reflux disease [19]. In a study with 58 patients with GERD (diagnosed by esophagitis and/or abnormal pH) compared to 51 controls, a salivary pepsin test was performed with an 81% positive predictive value and a 78% negative predictive value [20]. In our study, we initially defined the threshold of pepsin as 33 ng/mL through ROC analysis. Further analysis showed that salivary pepsin levels were significantly correlated with RFS/RSI scores which means that salivary pepsin measurements have compared well against RFS/RSI score system.