Sökning: "Theoretical"

Visar resultat 1 - 5 av 8750 avhandlingar innehållade ordet Theoretical.

1. 1. Theoretical Photochemistry : Halogenated Arenes, Phytochromobilin, Ru(II)polypyridyl complexes and 6-4 photoadducts

   Författare :Anders Borg; Sten Lunell; Hans Karlsson; Luis Serrano-Andrés; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; Quantum Chemistry; Halogenated Arenes; Phytochromobilin; Phytochrome; Ruthenium; 6-4 photoadducts; Photochemistry; Kvantkemi; Quantum chemistry; Kvantkemi;

   Sammanfattning : This thesis presents Quantum Chemical calculations on the Photochemistry of Halogenated benzenes, Phytochromobilin, Ruthenium Polypyridyl complexes and 6-4 photoadducts in DNA. The work is focused on improving the understanding of a number of experimentally observed photochemical processes in these systems. LÄS MER

3. 2. Biomimetic Iron Complexes involved in Oxygenation and Chlorination : A Theoretical Study

   Författare :Holger Noack; Margareta R. A. Blomberg; Per E. M. Siegbahn; Martin Kaupp; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; biomimetic; iron; density functional theory; intradiol; chlorination; adpic acid; diamond core; reactivity; Bio-inorganic chemistry; Bio-oorganisk kemi; Theoretical chemistry; Teoretisk kemi; kemisk fysik; Chemical Physics;

   Sammanfattning : Biomimetic chemistry is directed towards the simulation of enzymatic reactivity with synthetic analogues. In this thesis a quantum chemical method has been employed to study the mechanism of highly reactive iron-oxo complexes involved in oxygenation and chlorination of organic substrates. LÄS MER

4. 3. Theoretical Studies of Cytochrome P450

   Författare :Patrik Rydberg; Beräkningskemi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum chemistry; Proteins; enzymology; Proteiner; enzymologi; Theoretical chemistry; transition-state force field; peroxidase; theoretical chemistry; molecular dynamics; density functional theory; cytochrome P450; porphyrin; haem; heme; kvantkemi; Teoretisk kemi;

   Sammanfattning : The cytochromes P450 are a large enzyme family that is found in all living organisms and takes part in both endogenous and exogenous metabolism. They are primarily mono-oxygenases and perform a wide range of reactions. LÄS MER

5. 4. Theoretical aspects of tetrapyrrole biochemistry

   Författare :Kasper Jensen; Beräkningskemi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Proteiner; enzymologi; Theoretical chemistry; quantum chemistry; Teoretisk kemi; kvantkemi; enzymology; Proteins; protein; enzyme; density functional; Heme; B12;

   Sammanfattning : Modern theoretical simulations are able to provide significant insight into biochemical problems on a scale which continues to expand. With the aid of computer power and the sophisticated programs of researchers in the field, we have addressed a series of problems related to the so-called tetrapyrrole cofactors found in all living organisms. LÄS MER

7. 5. Theoretical studies of porphyrin proteins

   Författare :Emma Sigfridsson; Beräkningskemi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; molecular mechanics; quantum chemical calculations; electrostatic potential charges; atomic charges; ferrochelatase; cytochrome; myoglobin; Porphyrin; haem; QM MM; reorganisation energy; Theoretical chemistry; quantum chemistry; Teoretisk kemi; kvantkemi;

   Sammanfattning : Different aspects of porphyrin proteins have been studied with theoretical methods. For example, we have studied: - The importance of hydrogen bonds for the discrimination between carbon monoxide and molecular oxygen by myoglobin, the oxygen carrier in muscles, modelling the active site both in vacuum and in the protein matrix - The inner-sphere reorganisation energy during electron transfer for cytochromes compared to other electron-transfer proteins, such as blue copper proteins and Fe-S clusters - The role of porphyrin distortions in the reaction mechanism of ferrochelatase, the enzyme that inserts an iron ion into protoporphyrin IX to make haem - The interaction between different metal sites in ferrochelatase In these studies we have used density functional theory, classical force field methods, and a combination of quantum chemistry and molecular mechanics. LÄS MER