Overuse of polymer materials has caused increasing direct human exposure to bisphenol AP (BPAP). Through the contaminated environment and food chains, adverse effects BPAP on humans plants induce growing concerns. In this study, pepsin structure changes were exhaustively investigated by multi-spectral methods. Under mimic physiological conditions, a gradient intrinsic fluorescence quenching ind...

The gastric output of acid and pepsin in response to two doses of the cholinergic drug carbachol was measured before and two months after complete truncal vagotomy and pyloroplasty in eight patients with duodenal ulcer. After vagotomy the basal output of acid and pepsin was reduced and there was no stimulation of secretion by a subthreshold dose of carbachol (0.5 units/kg) nor was there an incr...

A histamine test meal is described for the estimation of the secretion of gastric acid and pepsin in the unanaesthetized intact rat. The stomach of the rat secreted pepsin and a small amount of acid in response to the test meal of hypertonic sucrose. Stimulation with histamine produced a pronounced rise in acid secretion but the output of pepsin remained unchanged. The increase in acid secretio...

objective(s): gastroesophageal reflux disease (gerd) is one of the most common digestive disorders that frequently lead to pulmonary complications due to gastric fluid aspiration. in the present experimental study, chronic aspiration of gastric fluid, its components and bile salts in rat lung was performed to find out the main factor(s) causing pulmonary complications of gastric fluid aspiratio...

A novel substrate, albumin complexed with bromphenol blue, has been developed for the assay of human gastric juice pepsin by a kinetic method in the Cobas centrifugal analyzer. The action of pepsin on the complex degrades the albumin and releases the dye. The change in the color of the substrate is a zero-order reaction. Human and porcine pepsin have different Km's with the new substrate. This ...

Concentrations of free and total hydrogen ions, total protein and pepsin were measured in gastric juice fractions collected during basal secretion and upon stimulation by graded doses of pentagastrin administered intravenously. Undissociated hydrogen ion and non-pepsin protein concentrations were calculated as derived quantities. The studies were carried out in nine patients with duodenal ulcer...

1. Evidence is presented that pepsin is a univalent acid with a value for pK of 6.85 (or a base, with pK 7.39). 2. The autodestruction of the pepsin is shown to be dependent in part upon an instantaneous irreversible change occurring in the ionized form of the enzyme (if it be an acid) or in the unionized form (if it be a base). 3. A further progressive autodestruction of pepsin at any given hy...

Modification of a single carboxylate side chain in pepsin by 1,2-epoxy-3Qnitrophenoxy)propane abolished enzymic activity. The degree of inactivation was related to incorporation of the modifier in a 1: 1 molar ratio. The essential residue was an aspartic acid which is contained in the amino acid sequence Ile-Val-Asp-Thr-Gly-Ser-Ser-Asn. The pH rate profile of enzymic inactivation suggested the ...

1. The inhibition of pepsin-catalysed hydrolysis of N-acetyl-l-phenylalanyl-l-phenylalanylglycine by the acyl product and product analogues was studied at pH4.3. 2. The acyl product, N-acetyl-l-phenylalanine, gives rise to linear competitive inhibition at pH4.3, whereas at pH2.1 it shows linear non-competitive behaviour. 3. The extent of transpeptidation to N-acetyl-l-[(3)H]phenylalanine during...

A method has been described for the isolation and crystallization of swine pepsin inhibitor from swine pepsinogen. Solubility experiments and fractional recrystallization show no drift in specific activity. The reversible combination of pepsin with the inhibitor was found to obey the mass law. The inhibitor is quite specific, failing to act on other proteolytic and milk clotting enzymes. The in...