Sökning: "Enzyme catalysis"

Visar resultat 11 - 15 av 167 avhandlingar innehållade orden Enzyme catalysis.

  1. 11. N-Heterocyclic Carbene Catalysis in Organic Synthesis - A Green Chemistry Approach

    Författare :Linda Ta; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; aerobic oxidation; ionic liquid; sustainability; NHC catalysis; oxidative NHC catalysis; green chemistry; OTHO; Organocatalysis;

    Sammanfattning : The twelve principles of green chemistry were created as a response to the multiple environmental issues caused by the release of waste from the chemical industry. The principles acts as a guide in the development of sustainable chemical processes for the syntheses of important molecules needed to sustain our living standards. LÄS MER

  2. 12. Theoretical Modeling of Enzyme Catalysis with Focus on Radical Chemistry

    Författare :Vladimir Pelmenschikov; Per E. M. Siegbahn; Tim Clark; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; density functional theory; enzyme catalysis; radical chemistry; zinc-containing peptidase; methyl-coenzyme M reductase; ribonucleotide reductase; superoxide dismutase; Quantum chemistry; Kvantkemi;

    Sammanfattning : Hybrid density functional theory (DFT) B3LYP method is applied to study the four diverse enzyme systems: zinc-containing peptidases (thermolysin and stromelysin), methyl-coenzyme M reductase, ribonucleotide reductases (classes I and III), and superoxide dismutases (Cu,Zn- and Ni-dependent enzymes). Powerfull tools of modern quantum chemistry are used to address the questions of biological pathways at their molecular level, proposing a novel mechanism for methane production by methyl-coenzyme M reductase and providing additional insights into hydrolysis by zinc peptidases, substrate conversion by ribonucleotide reductases, and biological superoxide dismutation. LÄS MER

  3. 13. Amine Transaminases in Biocatalytic Amine Synthesis

    Författare :Henrik Land; Per Berglund; Helen C. Hailes; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Amine Transaminase; Biocatalysis; Transamination; Reductive Amination; Enzyme; Enzyme Engineering; Equilibrium Displacement; Screening; Enzyme Stability; Bioteknologi; Biotechnology;

    Sammanfattning : The use of enzymes, nature´s own catalysts, both isolated or as whole cells to perform chemical transformations is called biocatalysis. As a complement to classical chemical catalysis, biocatalysis can be an environmentally friendly and more economical option in the production and synthesis of chemicals. LÄS MER

  4. 14. Probing the Alpha Class Glutathione Transferase Structure. Combinatorial Subunit Studies and Rational Redesign

    Författare :Ann Gustafsson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biochemistry; Glutathione transferases; rational redesign; enzyme; catalysis; Biokemi; Biochemistry; Biokemi; Molecular Biotechnology; molekylär bioteknik avd f jonfysik ;

    Sammanfattning : The present work concerns two Alpha class enzymes, GST A1-1 and GST A4-4, of the glutathione transferase (GST) family, which are detoxication enzymes catalyzing the conjugation of the tripeptide glutathione with various electrophiles. The GST A1-1 structure was explored for protein engineering purposes and tailored for increased activity toward alkenals. LÄS MER

  5. 15. Calculations of Reaction Mechanisms and Entropic Effects in Enzyme Catalysis

    Författare :Masoud Kazemi; Johan Åqvist; Per E. M. Siegbahn; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Enzyme catalysis; Entropy; Cytidine deamination; Ribosome; Peptidyl-tRNA hydrolysis; Peptide bond formation; Empirical valence bond method; Density functional theory; Biology with specialization in Structural Biology; Biologi med inriktning mot strukturbiologi; Biokemi; Biochemistry; Biology with specialization in Molecular Biotechnology; Biologi med inriktning mot molekylär bioteknik;

    Sammanfattning : Ground state destabilization is a hypothesis to explain enzyme catalysis. The most popular interpretation of it is the entropic effect, which states that enzymes accelerate biochemical reactions by bringing the reactants to a favorable position and orientation and the entropy cost of this is compensated by enthalpy of binding. LÄS MER