The preparation and purification of individual human pepsins by using diethylaminoethyl-cellulose

Roberts, Norman B.; Taylor, W.

doi:10.1042/bj1690607

Cited by 23 publications

(10 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3). Pentagastrin stimulated gastric juice from non-symptomatic volunteers (age [18][19][20], however, did not show such increased mucolytic activity above pH 4. Direct comparison of the results from the DU patients and non-symptomatic volunteers is not possible as they were not age matched.…”

Section: Resultsmentioning

confidence: 82%

Mucus degradation by pepsin: comparison of mucolytic activity of human pepsin 1 and pepsin 3: implications in peptic ulceration.

Pearson¹,

Ward²,

Allen³

et al. 1986

Gut

Self Cite

View full text Add to dashboard Cite

SUMMARY The ability to digest mucus, mucolytic activity of isolated pepsins and samples of human gastric juice has been assayed by measuring the fall in viscosity when incubated with purified pig gastric mucus glycoprotein. Pure human pepsin 1, the peptic ulcer associated pepsin, digested gastric mucus glycoprotein at a faster rate than did pure human pepsin 3 (the principal human pepsin), or the equivalent pig pepsin (pepsin A). At pH 2-0 pepsin 1 had twice the mucolytic activity of pepsin 3. Above pH 3X8 this difference became more marked and whereas pepsin 1 caused substantial mucolysis up to and including pH 5-1, pepsin 3 had minimal activity. At pH 4X0 pepsin 1 had six times the mucolytic activity of pepsin 3. Gastric juices from patients with duodenal ulcer each exhibited substantial mucolytic activity between pH 2 to 5, similar to that of pepsin 1. In contrast, gastric juice from non-symptomatic volunteers exhibited little mucolytic activity above pH 4. Analysis of the mucus glycoprotein by gel filtration showed that an increase in lower molecular weight, pepsin degraded, glycoprotein was associated with the fall in mucus viscosity for all enzyme preparations. These results showed that pepsin 1 can digest the mucus more effectively than pepsin 3 and at higher pH values. The raised concentrations of pepsin 1 in the juice of peptic ulcer patients may thus promote the ulcerative process by increased erosion of the mucus barrier under conditions likely to pertain in the duodenal bulb as well as the stomach.The mucus:bicarbonate barrier is considered to be an important component of the gastroduodenal mucosal defence mechanisms against autodigestion by the gastric juices.1-3 To function as an effective barrier the adherent mucus must be present as a continuous layer, a state maintained by a balance between its secretion from the epithelial cells and its erosion by removal from the surface into the lumen.4 Factors which swing this balance in favour of degradation of the adherent mucus might therefore be expected to decrease gastroduodenal mucosal resistance and result in mucosal damage. Agents identified in such adherent mucus erosion in vivo are proteolytic degradation and mechanical sloughing. Extensive in vitro studies show that luminal pepsins are mucolytic and dissolve adherent mucus gel by breaking down the polymeric structure

show abstract

Section: Resultsmentioning

confidence: 82%

Mucus degradation by pepsin: comparison of mucolytic activity of human pepsin 1 and pepsin 3: implications in peptic ulceration.

Pearson¹,

Ward²,

Allen³

et al. 1986

Gut

Self Cite

View full text Add to dashboard Cite

show abstract

“…977 HUMAN PEPSINS Electrophoretically homogeneous preparations of human pepsins 1, 3, and 5 and a mixture of pepsins 3 and 5 were kindly donated by Dr N. B. Roberts, who prepared them by chromatography of pooled human gastric juice on DEAE (diethylaminoethyl) cellulose using chloride gradient elution (Etherington and Taylor, 1969;Roberts and Taylor, 1978). PEPSTATIN Pepstatin (iso-valeryl-L-valyl-L-valyl-4 amino-3 hydroxy-6-methylheptanoyl-L-alanyl-4 amino-3 hydroxy-6 methyl heptanoic acid) was kindly donated as the sodium salt by Dr K. Goto and Dr H. Umezawa of the Banyu Pharmaceutical Co., Tokyo, Japan.…”

Section: Gastric Juicementioning

confidence: 99%

Pepsin 5 in gastric juice: determination and relationship to the alkali-stable peptic activity.

Walker¹,

Taylor²

1979

Gut

Self Cite

View full text Add to dashboard Cite

:SUMMARY Pure human pepsins 1 and 3 are inactivated by incubation at pH 7-1-7-3 for 30 minutes, losing 90 % or more of activity. Pepsin 5 is alkali-stable, retaining 100 % of activity. Mixtures of pure pepsins 1 and/or 3 with pepsin 5 were found to have greater alkali-stable activity than predicted. Two published methods for determining the alkali-stable fraction of the peptic activity of gastric juice gave, respectively, in our hands values of 45'4-80-0 % and 27-5-43 9 % of the total activity. These values seemed too high to be attributable only to pepsin 5 in gastric juice, as agar gel electrophoresis shows pepsin 3 to have the principal activity. Electrophoretograms of alkaline incubated gastric juice revealed that large amounts of pepsin 3 retained activity as well as pepsin 5, and a proteolytic zone '4' appeared between them. Alkali inactivation thus does not allow the estimation of pepsin 5 individually in gastric juice. Pepstatin, at a final concentration of 100 to 170 pmol/ml, may be used to estimate pepsin 5 in gastric juice and gave values of 18-0 to 27-6 % of the total peptic activity. Pepsin 5, in gastric juice and in mixtures of pepsins, appears to protect pepsin 3 from alkaline-inactivation, and to a lesser extent from pepstatin inhibition.

show abstract

“…Many researchers reported there existed many kinds of pepsinogen in the mucous membrane of the human stomach (Tang et al . 1959; Samloff 1969; Roberts and Taylor 1978; Samloff 1982). They were named from Pg1 to Pg7 according to electrophoretic mobility, and classed to PG I and PG II on the basis of immunological property.…”

Section: Resultsmentioning

confidence: 99%

ACTIVITY DISTRIBUTION OF DIGESTIVE PROTEASES FROM NEMIPTERUS VIRGATUS AND THEIR RESPONSES TO pH VALUE AND TEMPERATURE

Zhao

Wang

Yang

et al. 2008

J Food Process Engineering

View full text Add to dashboard Cite

In the present study, three groups (I-III) of Nemipterus virgatus, with average body weights of 154.36, 250.72 and 329.09 g, respectively, were used to investigate the changes in the activity and distribution of digestive proteases in different organs and sections of the digestive tract. Another group of N. virgatus (average body weight of 188.41 g) was used to analyze the changes in the activity of digestive proteases in response to various pH values and temperatures. The activity of digestive proteases in all analyzed organs increased with the increase of body weight at the range of 154.36-329.09 g. The activities of digestive proteases in the different sections of the digestive tract were compared, and a similar change was found among groups I-III. The activities of digestive proteases from various organs were in a descending order: pylorus ceca > stomach > foregut > midgut > hindgut > hepatopancreas. Through observing the zymograms of substrate-sodium dodecil sulphate-polyacrylamide gel electrophoresis, many kinds of digestive proteases could be found in different organs and the varieties were changed with the change of body weight. Two peaks in the diagram between protease activity and pH value were found at pH 3.0 and 10.0, respectively. The activity under alkaline condition was 60% higher than that under acidic condition. The optimal temperature for protease activity was 50C, while the protease activity at 10C was only 30% of that at 50C. 3 Corresponding

show abstract

The preparation and purification of individual human pepsins by using diethylaminoethyl-cellulose

Cited by 23 publications

References 30 publications

Mucus degradation by pepsin: comparison of mucolytic activity of human pepsin 1 and pepsin 3: implications in peptic ulceration.

Mucus degradation by pepsin: comparison of mucolytic activity of human pepsin 1 and pepsin 3: implications in peptic ulceration.

Pepsin 5 in gastric juice: determination and relationship to the alkali-stable peptic activity.

ACTIVITY DISTRIBUTION OF DIGESTIVE PROTEASES FROM NEMIPTERUS VIRGATUS AND THEIR RESPONSES TO pH VALUE AND TEMPERATURE

Contact Info

Product

Resources

About