Search results for "proteolysis"
showing 9 items of 119 documents
Limited Proteolysis of Human α2-HS Glycoprotein/Fetuin
1996
alpha2-HS glycoprotein is a major protein of human plasma whose function is still obscure. A proteolytically processed form of alpha2-HS glycoprotein lacking a segment of 40 amino acid residues bridging its heavy and light chain portions ("connecting peptide") has been described suggesting that this peptide is released by post-translational processing to fulfill biological role(s) of alpha2-HS glycoprotein. To test this hypothesis we investigated how the connecting peptide is released from the parental molecule by limited proteolysis. We developed monoclonal antibodies to various portions of the connecting peptide and its NH2-terminal flanking region which cross-react with the native alpha2…
Analysis of Structure-Activity Relationships of the Bowman-Birk Inhibitor of Serine Proteinases
1993
Proteinase inhibitors are a class of the various dietary inhibitors of mutagenesis and carcinogenesis (Hayatsu et al., 1988). Schelp and Pongpaew (1988) have recently hypothesized that protection against cancer may result from an increase of endogenous proteinase inhibitors such as α2-macroglobulin induced by diets that are low in calories and fat. The Bowman-Birk inhibitor (BBI) of serine proteinases, a double-headed polypeptide-inhibitor of trypsin and chymotrypsin, is one of the most potent cancer chemopreventive agents (Yavelow et al., 1983, 1985). Recently, this property has been substantiated in an in vivo investigation using mice (St. Clair et al., 1990) that were exposed to dimethyl…
Molecular response to TBT stress in marine sponge Suberites domuncula: proteolytical cleavage and phosphorylation of KRS_SD protein kinase
2003
Abstract Marine sponges as sessile filter feeders are inevitably under a constant influence of changes in their environment. Mediation of extracellular signals and regulation of cellular response to environmental stress is a key function of cellular protein kinases. Expression, proteolytical cleavage and phosphorylation of stress-responsive KRS_SD protein kinase, in control and tributyl-tin (TBT) treated sponges were investigated. In control sponge, two KRS_SD proteins were expressed: KRS_SD1 (54 kDa) corresponding to KRS_SD calculated molecular weight, and KRS_SD2 (50 kDa). Exposure of sponges to TBT resulted in alteration of KRS_SD1 and KRS_SD2 expression levels and their phosphorylation …
RASSF1A inhibits estrogen receptor alpha expression and estrogen-independent signalling: implications for breast cancer development
2012
The Ras association domain family 1 isoform A (RASSF1A) is a tumor suppressor whose inactivation is implicated in the development of many human cancers, including breast carcinomas. Little is known about the tumor-suppressive function of RASSF1A in breast tissue and whether its inactivation is mechanistically involved in the initiation and progression of breast tumors. Here, we show that RASSF1A inhibits breast cancer growth in vivo, and suppresses estrogen receptor (ERα) expression and function. Reconstitution of RASSF1A in MCF7 cells led to decreased ERα levels and reduced sensitivity to estrogen (E2). Concomitantly, we observed decreased expression of Id1 as well as the E2-responsive gen…
Characterization of a profile of epigenetic alterations involved in the aetiopathogenesis of endometriosis. Validation of molecular biomarkers for di…
2018
Introduction: Endometriosis is an oestrogen-dependent inflammatory disorder defined by the presence of endometrial-like tissue in ectopic locations, which limits the quality of life of affected women. This pathology affects 10% of reproductive-age women from all ethnic and social groups, although the prevalence in those patients experiencing pain, infertility or both is as high as 35%-50%, being the estimated prevalence of this condition around 176 million worldwide. Endometriosis is associated with an average diagnostic delay of 7 years, what could be partially explained by the lack of non-invasive biomarkers for diagnose, since the gold standard method is laparoscopy followed by histologi…
Lipodepsipeptides from Pseudomonas syringae are partially proteolyzed and are not absorbed by humans: An in vitro study
2008
There are some concerns about the use of Pseudomonas-based products as biocontrol agents because of the hemolytic activity shown by their metabolites. The effects of Pseudomonas lipodepsipeptides (LDPs) on mammals via ingestion and the LDP degradation during the digestion and intestinal permeability have not been evaluated. In this research, the susceptibility of different LDPs to degradation was assayed with enzymatic gastrointestinal digestion, and intestinal permeability to LDPs was investigated in an in vitro system based on an intestinal cell layer system. Results demonstrated that trypsin and chymotrypsin hydrolyze up to 50% of the various LDPs, and that proteolysis was further increa…
Sodium Chloride and Magnesium Chloride affected by Ripening of Camembert Cheese
1993
Ripening of cheese with three kinds of salt treatment was studied using MgCl 2 , NaCl or a mixture of the two. Proteolysis was followed by determination of TCA-soluble nitrogen and quantitative electrophoresis. A rapid one-step method for free fatty acids was used to determine short and long-chin fatty acids. In the presence of magnesium, proteolysis increased, even with NaCl, which seemed to delay the magnesium activation. Lipolysis was retarded by NaCl, which decreased the level of free fatty acids. An imbalance between proteolysis and lipolysis could be responsible for the unpleasant flavor of the cheese containing both MgCl 2 and NaCl
Regulated Proteolysis of RAGE and AβPP as Possible Link Between Type 2 Diabetes Mellitus and Alzheimer's Disease
2009
Epidemiological studies have linked type 2 diabetes mellitus (T2DM) with an increased risk of developing Alzheimer's disease (AD). In T2DM, the elevated blood glucose level promotes formation of advanced glycation end products (AGEs). The receptor for AGEs (RAGE) is a type I membrane-protein and is also able to import amyloid-beta (Abeta) from the blood across the blood-brain-barrier into the brain. Oligomeric Abeta peptides disturb synaptic function in the brain and are believed to contribute to the development of AD. Abeta peptides are released from the amyloid-beta protein precursor (AbetaPP) after sequential proteolysis by beta- and gamma-secretases but alpha-secretase-mediated cleavage…
Cholesterol as stabilizer of the oxytocin receptor
2002
AbstractThe function of the oxytocin receptor system is strongly dependent on steroids as demonstrated by several physiological studies. One key element of this dependence on steroids may be the interaction of cholesterol and the oxytocin receptor. In this study, we show that cholesterol stabilizes the solubilized human oxytocin receptor against thermal inactivation and proteolytic degradation. In the absence of additional cholesterol, the soluble receptor inactivates within minutes. Maximal stabilization of the oxytocin receptor requires a continuous supply with cholesterol from a cholesterol-rich environment. A structure–activity analysis of various cholesterol analogues and their effect …