Gastroesophageal reflux disease is mediated principally by acid. Today, we recognise reflux reaches beyond the esophagus, where pepsin, not acid, causes damage. Extraesophageal reflux occurs both as liquid and probably aerosol, the latter with a further reach. Pepsin is stable up to pH 7 and regains activity after reacidification. The enzyme adheres to laryngeal cells, depletes its defences, an...

The relationship between the secretion of pepsin 1 (the most electronegative of the pepsins), and the smoking habits of 219 patients has been investigated. Significantly more cigarette smokers with peptic ulceration (72.5%) secreted pepsin 1 in greater than trace amounts after pentagastrin or histamine than did non-smokers with ulceration (51.2%). Differences of a similar order were found for m...

The structure of porcine pepsin crystallized in the presence of dimethyl sulphoxide has been analysed by X-ray crystallography to obtain insights into the structural events that occur at the onset of chemical denaturation of proteins. The results show that one dimethyl sulphoxide molecule occupies a site on the surface of pepsin interacting with two of its residues. An increase in the average t...

The techniques of crystallization, developed in recent years, have permitted enzyme studies that are far more exact than were possible with the more crude preparations. Among the crystalline enzymes, Northrop’s pepsin has been the object of widespread and intensive research (1) which has contributed to the knowledge of enzyme action and mode of operation. In order to further the understanding o...

BACKGROUND None of current diagnostic methods has been proven to be a reliable tool for gastro-esophageal reflux disease (GERD). Pepsin in saliva has been proposed as a promising diagnostic biomarker for gastro-esophageal reflux. We aimed to determine the diagnostic value of salivary pepsin detection for GERD. METHODS Two hundred and fifty patients with symptoms suggestive of GERD and 35 asym...

Crystalline 60 per cent active acetyl pepsin has 7 acetyl groups per mol of pepsin, 3 of which are readily hydrolyzed in acid at pH 0.0 or in weak alkali at pH 10.0. The tyrosine-tryptophane content of this acetylated pepsin, measured colorimetrically, is less than pepsin by three tyrosine equivalents. Hydrolysis at pH 0.0 or pH 10.0 of the 3 acetyl groups results in a concomitant increase in t...

Background Laryngopharyngeal reflux (LPR) causes chronic cough, throat clearing, hoarseness, and dysphagia can promote laryngeal carcinogenesis. More than 20% of the US population suffers from LPR there is no effective medical therapy. Pepsin a predominant source damage during which disrupts barrier function potentially via E-cadherin cleavage proteolysis downstream matrix metalloproteinase (MM...

The decrease in protein nitrogen and in the activity of solutions of crystalline pepsin at pH 1.8 and 45 degrees C. has been determined. The decrease in activity, as measured with eleven different methods, is in exact proportion to the decrease of protein nitrogen of the solution. The measurements were continued until less than 5 per cent of the original protein remained. These results indicate...

Commercial samples of crystalline swine pepsin have been found to be heterogeneous by a number of criteria. Several active fractions can be obtained by chromatography on hydroxylapatite with phosphate buffers, pH 5.7, of increasing molarity as eluents. This has been found to be an effective procedure for evaluating the homogeneity of pepsin. End group analysis by the cyanate method yields 1 eq ...