Avancerad sökning

Hittade 5 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Studies on nucleoside H-phosphonoselenoate chemistry and chalcogen exchange reaction between P(V) and P(III) compounds

   Författare :Martin Kullberg; Jacek Stawinski; Wojciech Markiewicz; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Phosphorus chemistry; H-phosphonate; H-phosphonoselenoate; nucleotide analogues; selenization; selenium transfer; phosphoroselenoate; Organic chemistry; Organisk kemi;

   Sammanfattning : In this thesis, the chemistry of compounds containing P-Se bonds has been studied. As a new addition to this class of compounds, H-phosphonoselenoate monoesters, have been introduced and two synthetic pathways for their preparation have been developed. LÄS MER

3. 2. Regenerable Organochalcogen Antioxidants : An Explorative Study

   Författare :Jiajie Yan; Lars Engman; David J. Procter; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; autoxidation; antioxidant; selenium; tellurium; regenerable; multifunctional; radical-trapping; hydroperoxide-decomposing; co-antioxidant; Chemistry with specialization in Organic Chemistry; Kemi med inriktning mot organisk kemi;

   Sammanfattning : Antioxidants are widely used to protect organic materials from damages caused by autoxidation, an oxidation process that occurs under normal aerobic conditions. In this thesis, novel multifunctional organoselenium and organotellurium antioxidants were designed, synthesized, and evaluated in search for compounds with better radical-trapping capacity, regenerability, and hydroperoxide-decomposing ability. LÄS MER

4. 3. Selenium in mammalian thioredoxin reductase

   Författare :Liangwei Zhong; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :;

   Sammanfattning : Thioredoxin reductase (TrxR) is a major enzyme in regulating intracellular redox status. The enzyme from several mammalian tissues has been purified, showing higher molecular weight and a much broader substrate specificity than E. coli TrxR, but the structural basis of these properties remained unknown. LÄS MER

5. 4. Development of Biomimetic Catalytic Systems for Selective Oxidations with H2O2 and O2

   Författare :Mikael Johansson; Jan-Erling Bäckvall; Matthias Beller; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biomimetic oxidations; catalyst immobilization; dihydroxylation; sulfoxidation; flavin; Chemistry; Kemi; Organic Chemistry; organisk kemi;

   Sammanfattning : Four different catalytic systems were studied for biomimetic coupled oxidations using H2O2 or O2. In the first example, osmium tetroxide works as a substrate-selective catalyst for dihydroxylation of olefins. Electron transfer to H2O2 is facilitated by electron transfer mediators (ETMs). LÄS MER

7. 5. Development of a Sel-tag for multimodality imaging and studies of mammalian thioredoxin reductase 1

   Författare :Qing Cheng; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :;

   Sammanfattning : Selenocysteine (Sec; U in one-letter code), the 21st amino acid existing in all selenoproteins, has unique biochemical properties due to its selenium atom, including a low pKa and a high reactivity with many electrophilic agents. When a selenoprotein is translated, the insertion of Sec occurs at a UGA codon, normally yielding translational termination. LÄS MER