Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1389183 (autodigestion)
 317 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aceglutamide aluminium (AGA, KW-110, Glumal) at doses of 30-100 mg/kg p.o. prevented the formation of the gastric lesions induced by three noxious compounds, ethanol, HCl and acidified taurocholate, all dose-dependently. The preventive effect of AGA against taurocholate-induced lesions was more marked than that against the other two noxious agents. AGA at the cytoprotective doses caused almost no decrease of the gastric acid secretion in both pylorus-ligated and non-ligated rats. AGA stimulated gastric mucus secretion and prevented the increment of back-diffusion of hydrogen ion into the mucosa significantly. These data indicate that AGA caused a cytoprotective effect not through the suppression of acid secretion but through the augmentation of the defense of the mucosa against autodigestion by gastric juice. In addition, pretreatment with indomethacin diminished the cytoprotective effect of AGA almost completely. This result suggests that the mechanisms of AGA's cytoprotection may be concerned with endogenous prostaglandins.
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PMID:Gastric cytoprotection of aceglutamide aluminium in rats. 381 9

It has been shown that when purified polyoma (Py) virions are dissociated by incubation in 150 mM NaCl-50 mM Tris-HCl (pH 8.5) containing 1 mM EGTA and 3 mM DTT, two new polypeptides (MW 43.5K and 40K) are produced by proteolysis of virion polypeptide VP1. Proteolysis is blocked by diisopropyl fluorophosphonate (DFP) and phenylmethyl sulfonyl fluoride (PMSF), suggesting that the virion-associated enzyme is a serine protease. When Py virions were dissociated in the presence of radiolabeled DFP, only VP1 became labeled to any significant extent, which suggests that the protease activity is a property of this viral polypeptide and that the 43.5K and 40K species are produced by autodigestion.
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PMID:Evidence that polyoma polypeptide VP1 is a serine protease. 633 Sep 84

The barrier that protects the undamaged gastroduodenal mucosa from autodigestion by gastric juice is a dynamic multicomponent system. The major elements of this barrier are the adherent mucus gel layer, which is percolated by the HCO3- secretion from the underlying epithelial cells; the epithelial layer itself, which provides a permeability barrier and can rapidly repair superficial damage by a process of cell migration referred to as reepithelization or restitution; and a specially adapted vasculature, which provides a supply of HCO3- for transcellular transport and/or diffusion into the mucus layer. Passive diffusion of intestinal HCO3- into the lumen is particularly important when there is superficial damage resulting in increased leakiness of the mucosal epithelium. The process of reepithelization occurs by the migration of performed cells from gastric pits or duodenal crypts. This process is quite distinct from the wound healing and associated inflammatory response that accompany more severe injury or chronic damage. The adherent mucus gel acts as a physical barrier against luminal pepsin and provides a stable unstirred layer that supports surface neutralization of acid by mucosal HCO3-. Surface neutralization by mucosal HCO3- provides a major mechanism of protection against acid in the proximal duodenum. In the stomach, where luminal acidity can fall to around pH 1, other mechanisms of protection must exist, since the surface pH gradient is reported to collapse when luminal H+ exceeds approximately 10 mM. This collapse of the surface pH gradients may reflect, at least in part, that such studies have been mostly performed on non-acid-secreting mucosa where the supply of HCO3- to the interstitium from the parietal cells will be reduced. However, because the gastric mucosa can withstand prolonged exposure to acid without apparent damage, this implies an intrinsic resistance of the epithelial apical surface. This is amply illustrated within the gastric glands that do not secrete mucus and HCO3- yet are exposed to undiluted pepsin and an isotonic solution of HCl. Bicarbonate and mucus secretions together with mucosal blood flow are under paracrine, endocrine, and neural control. The rate of reepithelialization will depend on local chemotactic factors, adhesion mechanisms, and the creation of an acid/pepsin/irritant-free environment under a protective gelatinous or mucoid cap. If optimal conditions are met, then the rate of reepithelialization appears to depend primarily on the intrinsic properties of the migrating cells themselves rather than control by exogenous mediators.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Gastroduodenal mucosal protection. 841 27

An aqueous extract of human placenta, used as wound healer, shows stabilization of trypsin against autodigestion as one of the peptides of the extract binds very strongly with the protease. Trypsin retains 40% of activity at constant level between 20 and 26 days in presence of the extract against complete inactivation in its absence. Inhibition of esterolytic activity and inability to react with p-nitrophenyl-p'-guanidinobenzoate, HCl, an active site directed reagent, by trypsin in presence of a peptide fraction of the extract indicated blocking of the catalytic site of the enzyme. Rayleigh scattering, size-exclusion HPLC, fluorescence resonance energy transfer, and surface plasmon resonance show that fibronectin type III-like peptide present in the extract interacts with trypsin. The peptide-trypsin complex is dissociated in presence of high concentration of substrates. Thus, regulation of trypsin activity by the placental extract is evident.
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PMID:Regulation of trypsin activity by peptide fraction of an aqueous extract of human placenta used as wound healer. 2152 55