Temat: covalent binding - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Metabolic activation of adriamycin by NADPH-cytochrome P450 reductase; overview of its biological and biochemical effects.
Autorzy:: Bartoszek, Agnieszka
Powiązania:: https://bibliotekanauki.pl/articles/1043757.pdf
Data publikacji:: 2002
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: covalent binding to macromolecules
adriamycin
oxygen radicals
NADPH-cytochrome P450 reductase
Opis:: NADPH-cytochrome P450 reductase (P450 reductase) is one of the enzymes implicated in the metabolism of adriamycin, a very important clinically used antitumour drug. However, apart from the enzyme involvement, so far little was known about the chemical route and biochemical effects of this process. We demonstrated that the application of P450 reductase simultaneously with adriamycin to tumour cells in culture significantly increased cytotoxicity of the drug. Under tissue culture conditions, we noticed also that, in the presence of P450 reductase, adriamycin metabolite(s), displaying an altered spectrum within the visible light range were formed. This observation was taken adavantage of to study the metabolism of adriamycin in cell-free systems, using initially the enzyme isolated from rat liver and the recently obtained recombinant human P450 reductase. The reductive conversion of the drug turned out to be a multi-stage process, which occurred only under aerobic conditions and was accompanied by excessive NADPH consumption. Further research carried out with the aid of radical scavengers and radiolabelled adriamycin revealed that the enhancement of biological activity of adriamycin by P450 reductase stemmed from the formation of alkylating metabolite(s) rather than from the promotion of redox cycling known to be induced in the presence of anthracyclines.
Źródło:: Acta Biochimica Polonica; 2002, 49, 2; 323-331
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Ocena wydajności immobilizacji inwertazy wiązanej kowalencyjnie na różnych nośnikach
Assessment of the immobilization yield of invertase covalently bound to different carriers
Autorzy:: Raducka, A.
Karcz, J.
Powiązania:: https://bibliotekanauki.pl/articles/2070485.pdf
Data publikacji:: 2009
Wydawca:: Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:: immobilizacja enzymu
wydajność
inwertaza
wiązanie kowalencyjne
enzymes immobilization
invertase
covalent binding
immobilization yield
Opis:: W pracy analizowano na podstawie danych literaturowych wydajność immobilizacji inwertazy wiązanej kowalencyjnie na różnych nośnikach. Spośród porównywanych nośników, najlepszym pod względem ilości wiązanej inwertazy okazał się modyfikowany chemicznie żel krzemionkowy (GA-N-CSMG).
The immobilization yield of invertase covalently bound to different carriers, was analysed in the paper on basis of literature data. Taking into account the amount of bonded invertase the best carrier among compared ones appeared to be chemically modified silica-gel (GA-N-CSMG).
Źródło:: Inżynieria i Aparatura Chemiczna; 2009, 3; 91-92
0368-0827
Pojawia się w:: Inżynieria i Aparatura Chemiczna
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Calcium-binding calmyrin forms stable covalent dimers in vitro, but in vivo is found in monomeric form.
Autorzy:: Sobczak, Adam
Blazejczyk, Magdalena
Piszczek, Grzegorz
Zhao, Gang
Kuznicki, Jacek
Wojda, Urszula
Powiązania:: https://bibliotekanauki.pl/articles/1041431.pdf
Data publikacji:: 2005
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: covalent dimer
calmyrin monomer
human lymphocytes
EF-hand calcium-binding proteins
Opis:: The EF-hand Ca^(2+)-binding protein calmyrin is expressed in many tissues and can interact with multiple effector proteins, probably as a sensor transferring Ca^(2+) signals. As oligomerization may represent one of Ca^(2+)-signal transduction mechanisms, we characterised recombinant calmyrin forms using non-reducing SDS/PAGE, analytical ultracentrifugation and gel filtration. We also aimed at identification of biologically active calmyrin forms. Non-reducing SDS/PAGE showed that in vitro apo- and Ca^(2+)-bound calmyrin oligomerizes forming stable intermolecular disulfide bridges. Ultracentrifugation indicated that at a 220 µM initial protein concentration apo-calmyrin existed in an equilibrium of a 21.9 kDa monomer and a 43.8 kDa dimer (trimeric or tetrameric species were not detected). The dimerization constant was calculated as Ka = 1.78 × 103 M^(-1) at 6oC. Gel filtration of apo- and Ca^(2+)-bound calmyrin at a 100 µM protein concentration confirmed an equilibrium of a monomer and a covalent dimer state. Importantly, both monomer and dimer underwent significant conformational changes in response to binding of Ca^(2+). However, when calmyrin forms were analyzed under non-reducing conditions in cell extracts by Western blotting, only monomeric calmyrin was detected in human platelets and lymphocytes, and in rat brain. Moreover, in contrast to recombinant calmyrin, crosslinking did not preserve any dimeric species of calmyrin regardless of Ca^(2+) concentrations. In summary, our data indicate that although calmyrin forms stable covalent dimers in vitro, it most probably functions as a monomer in vivo.
Źródło:: Acta Biochimica Polonica; 2005, 52, 2; 469-476
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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