Pepsin-catalyzed transpeptidation was studied by high resolution 75 MHz 13C nuclear magnetic resonance spectroscopy. Enrichment with 13C at the carbonyl carbons of the substrates Leu-Tyr-NH2 and Leu-Leu-NH2 facilitated detection and identification of the transpeptidation and hydrolysis products of enzymic action. Porcine pepsin was found in each case to synthesize and release the tetrapeptide L...

In an earlier paper (1) the writer reported the isolation of/-mono-iodotyrosine from an alkaline hydrolysate of very slightly iodinated pepsin. Since then Harington and Pitt Rivers (2) have synthesized/-mono-iodotyrosine and dlmono-iodotyrosine and a comparison of the properties of their compounds with those reported by us led them to conclude that for the compound from pepsin "the nature remai...

The effects of fundic vagotomy on acid and pepsin secretion in 12 patients (10 males, two females; nine duodenal ulcer, three gastric ulcer) were studied using a pentagastrin dose response before and after Vagotomy. In the intact stage H, Cl, and pepsin output all had the same ED50, 120-127 pmol/kg/h. Vagotomy reduced basal output of acid by 78%, Cl- by 50%, and pepsin by 62%. Postvagotomy basa...

OBJECTIVE/HYPOTHESIS Pepsin lateral flow device (LFD) is a rapid noninvasive test to detect salivary pepsin as a surrogate marker for gastroesophageal reflux disease (GERD). We aimed to establish the test sensitivity, specificity, positive and negative predictive values (PPV, NPV) in patients with symptomatic and objective evidence of GERD compared to healthy controls. STUDY DESIGN Prospectiv...

OBJECTIVES/HYPOTHESIS To determine salivary pepsin levels as a function of collection time. STUDY DESIGN A prospective, case-control study. METHODS We selected 57 patients with clinical symptoms and signs of laryngopharyngeal reflux who underwent 24-hour multichannel intraluminal impedance-pH (24h MII-pH) monitoring tests, and 12 control subjects without clinical symptoms and signs of laryn...

1. Synthesis of plastein from the products of peptic hydrolysis of small quantities of egg albumin can be demonstrated with amorphous or crystalline pepsin. 2. Synthesis of plastein from the products of peptic hydrolysis of amorphous or crystalline insulin can be demonstrated with amorphous or crystalline pepsin. 3. The plastein synthesised by pepsin from the products of peptic hydrolysis of in...

The objective of this study was to investigate the influence of the concentration of Al ions and the substrate/enzyme ratio on pepsin and trypsin activity in vitro. The experimental design was a combination of three Al ion concentrations (0.25; 2.5 and 25.0 μg Al/ml of reaction solution) and two substrate/enzyme ratios (S/E = 10 and 100 for pepsin, and 100 and 1000 for trypsin). Enzymatic activ...

Chicken pepsinogen was extracted from the forestomach of chicken and purified by the consecutive application of acetone precipitation, chromatography on diethylaminoethyl cellulose, and gel filtration on Sephadex G-100. The purified pepsinogen was homogeneous on disc electrophoresis and sedimented as monodisperse material. Chicken pepsin was obtained by the activation of the pure zymogen at pH ...

A study of the inactivation of trypsin and chymotrypsin by high pressures was reported previously (1). The effects of high pressure on pepsin and chymotrypsinogen, and on the activation of chymotrypsinogen by trypsin, have now been examined. The effect of high pressure on crystalline pepsin was investigated by Matthews, Dow, and Anderson (2), in particular as affected by magnitude of pressure a...