National Repository of Grey Literature 32 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Structure and Function of Glutamate Carboxypeptidase II
Šácha, Pavel ; Konvalinka, Jan (advisor) ; Šedo, Aleksi (referee) ; Blahoš, Jaroslav (referee)
4 Závěr GCPII je důležitý protein, který hraje roli v mnoha fyziologických i patologických procesech. Proto bylo třeba získat větší množství enzymaticky aktivního proteinu pro jeho další biochemický výzkum. Heterologní expresí v hmyzích buňkách S2 bylo exprimováno a následně purifikováno dostatečné množství velmi čistého a aktivního enzymu. To umožnilo jeho biochemickou charakterizaci, krystalizaci a později vedlo i k vyřešení krystalové struktury. GCPII je aktivní v širokém rozmezí pH 6 - 8, s maximem kolem pH 7,5. Zjistili jsme, že kromě přirozeného substrátu Ac-Asp-Glu GCPII štěpí také acetylované dipeptidy Ac-Asp-Met, Ac-Glu-Met, Ac-Glu-Glu, Ac-Ala-Glu a Ac-Ala-Met. U těchto substrátů byly změřeny kinetické parametry štěpení. Nalezení dalších substrátů může vést k objevení dosud nepopsaných fyziologických rolí GCPII. Také byly porovnány hodnoty IC50 inhibitorů známých z literatury u námi připravené GCPII a GCPII izolované z potkaních mozků. IC50 bylo u všech méně specifických inhibitorů nižší u rekombinantní GCPII než u GCPII izolované z mozků. Rozdíly ve výsledcích vysvětlujeme vazbou méně specifických inhibitorů na jiné proteiny preparátů z mozku. Vůbec nepochybujeme o tom, že data získaná za použití čistého rekombinantního proteinu jsou přesnější než ta, ktará byla získána ze špatně definovaných...
Development of inhibitors of rhomboid proteases as tools for the study of their biological functions
Tichá, Anežka ; Stříšovský, Kvido (advisor) ; Šedo, Aleksi (referee) ; Konvalinka, Jan (referee)
Rhomboids are intramembrane serine proteases that belong to the evolutionarily widespread rhomboid superfamily. Rhomboids developed a slightly different catalytic mechanism compared to classical serine proteases; they utilise a catalytic dyad (Ser/His) instead of the common triad (Ser/His/Asp), and the rhomboid active site is buried in the membrane. This, coupled with their hydrophobicity, makes them quite difficult to study. Therefore, even though they are known to be involved in several important biological processes it is still not clear how exactly most of them are involved in the regulation of or in the pathologies of diseases related to these processes (such as malaria, Parkinson's disease or cancer). Our understanding is hindered by the lack of tools for their characterisation both in vitro and in vivo. In my thesis I present new fluorogenic substrates based on the LacYTM2 sequence, which is hydrolysed by several different rhomboid proteases. Using Förster resonance energy transfer (FRET)-based methods, these substrates are suitable for continuous monitoring of rhomboid activity in vitro. Modifications in the P5-P1 residues can improve selectivity for a specific rhomboid, the choice of FRET pair of fluorophores that absorbes light of longer wavelengths makes them suitable for high throughput...
Expression and function of serpin B9 in lung carcer cells
Roušalová, Ilona ; Křepela, Evžen (advisor) ; Šedo, Aleksi (referee) ; Kotyza, Jaromír (referee)
Background: Granzyme B (GrB) is a key proapoptotic secretory protease of CTLs and NK cells. Its specific proapoptotic effects in cancer cells can be blocked by increased expression of serpinB9. SerpinB9 gene expression can be transcriptionally upregulated by some interleukins and by the oestrogen activated oestrogen receptor-α (ERα) in cells which express ERα protein. The aims of my thesis were to evaluate the expression of SB9 and to examine its inhibitory activity against exogenous active GrB in non-small cell lung carcinoma (NSCLC) cell lines and tissues. To analyse the expression status of GrB mRNA in NSCLC cell lines and tissues. To investigate the role of estradiol-17β (E2), selected ILs and DNA methylation in regulation of SB9 expression in NSCLC cells. The apoptosome apparatus is a cell death signalling platform activates the initiator procaspase-9. Activation of the apoptosome apparatus is often impaired in various types of cancer but the molecular basis of its suppression is still unknown. APIP and UACA/nucling belong to the endogenous regulators of apoptosome apparatus. The aim of my thesis was to investigate whether DNA methylation is involved in the transcriptional regulation of expression of APIP and UACA genes in NSCLC cell lines. Methods: Following methods were used in this thesis:...
Definition of the expression pattern of DASH system in transformed glial cells, the coupled expression of fibroblast activation protein and dipeptidyl peptidase-IV.
Balážiová, Eva ; Šedo, Aleksi (advisor) ; Borovanský, Jan (referee) ; Mareš, Vladislav (referee)
Dipeptidyl peptidase-IV (DPP-IV) is a multifunctional transmembrane glycoprotein removing X-Pro dipeptide from the amino-terminus of the peptide chain. This evolutionary conserved sequence protects a number of biologically active peptides against the unspecific proteolytic cleavage. DPP-IV belongs into the group of "Dipeptidyl peptidase-IV Activity and/or Structure Homologues" (DASH), which, except the canonical DPP-IV, comprises fibroblast activation protein-α/seprase (FAP), and several other molecules. However several of DASH molecules are the enzymes, they execute at least some of their biological functions by non-proteolytic protein-protein interactions. DASH molecules, their substrates and binding partners are parts of "DASH system" which is affected in several pathological process including a cancer. Specifically DPP-IV and its closest structural relative FAP are among others expected to be involved in the development and progression of malignant glioma. In this study we showed the expression and colocalization of DPP-IV and FAP in glioma cells in vitro and in human high grade gliomas. In addition to the DPP-IV/FAP double positive transformed glial cells, we also identified a subpopulation of FAP positive mesenchymal cells located in the perivascular compartment. Moreover we described the...
Dipeptidyl peptidase IV in orthotopic models of glioma
Hilšer, Marek ; Šedo, Aleksi (advisor) ; Mandys, Václav (referee) ; Šefc, Luděk (referee)
Malignant gliomas belong to a highly aggressive class of tumours. Average patient survival time generally does not exceed 15 months. Despite intensive research, no therapeutic strategies capable of significantly extending the lives of those affected by the disease have been established to date. One potentially viable area of research into possible therapeutic targets in cancer therapy focuses on cell surface proteases. This group of proteins includes dipeptidyl peptidase IV (DPP-IV). Changes to DPP-IV expression have been established in the case of various cancer types including malignant gliomas. Understanding the role of DPP-IV in the biological processes of this malignant disease may thus contribute to the development of new therapeutic modalities. This thesis is therefore dedicated to establishing an orthotopic xenograft model as well as a genetically engineered model (GEM) of the glioma. The effects of DPP-IV on the growth of an experimental glioma were subsequently examined, as was the ratio of catalytic and non- catalytic mechanisms in this process. The GEM model was used for monitoring enzymatic activity and DPP-IV distribution. Non-invasive fluorescence imaging was employed in order to monitor the intraexperimental dynamics of experimental gliomas. The results indicated that DPP-IV...
"DASH molecues" in local and systemic pathogenetic processes of rehumatoid arthritis
Šromová, Lucie ; Šedo, Aleksi (advisor) ; Borovanský, Jan (referee) ; Prokešová, Ludmila (referee)
The biological half-life of several pro-inflammatory mediators involved in the pathogenesis of rheumatoid arthritis (RA) is controlled by molecules exhibiting dipeptidyl peptidase-IV (DPP-IV)-like enzymatic activity (Dipeptidyl peptidase-IV activity and/or structure homologues- DASH). The aim of this thesis was to identify the molecular source of the DPP-IV-like enzymatic activity in the peripheral blood and synovial fluid in patients with rheumatoid arthritis as compared to control patients with osteoarthritis (OA), and to evaluate the association of DPP-IV with the disease activity. We found that the main source of the DPP-IV-like enzyme activity in the plasma and in the synovial fluid in patients with RA is the canonical DPP-IV. DPP-IV-like enzymatic activity and canonical DPP-IV were also detected on the cell surface of blood and synovial fluid mononuclear cells. Significantly lower DPP-IV-like enzymatic activity and DPP-IV expression in the synovial fluid mononuclear cells was found in RA as opposed to OA patients. In the synovial fluid of RA patients there was also a negative correlation between the concentration of the pro-inflammatory DPP-IV substrate SDF (stromal cell-derived factor-1 and the proportion of the DPP-IV+ T cells. The blood plasma DPP-IV-like enzymatic activity and...
Development of inhibitors of rhomboid proteases as tools for the study of their biological functions
Tichá, Anežka ; Stříšovský, Kvido (advisor) ; Šedo, Aleksi (referee) ; Konvalinka, Jan (referee)
Rhomboids are intramembrane serine proteases that belong to the evolutionarily widespread rhomboid superfamily. Rhomboids developed a slightly different catalytic mechanism compared to classical serine proteases; they utilise a catalytic dyad (Ser/His) instead of the common triad (Ser/His/Asp), and the rhomboid active site is buried in the membrane. This, coupled with their hydrophobicity, makes them quite difficult to study. Therefore, even though they are known to be involved in several important biological processes it is still not clear how exactly most of them are involved in the regulation of or in the pathologies of diseases related to these processes (such as malaria, Parkinson's disease or cancer). Our understanding is hindered by the lack of tools for their characterisation both in vitro and in vivo. In my thesis I present new fluorogenic substrates based on the LacYTM2 sequence, which is hydrolysed by several different rhomboid proteases. Using Förster resonance energy transfer (FRET)-based methods, these substrates are suitable for continuous monitoring of rhomboid activity in vitro. Modifications in the P5-P1 residues can improve selectivity for a specific rhomboid, the choice of FRET pair of fluorophores that absorbes light of longer wavelengths makes them suitable for high throughput...

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