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1. 1. Quantum chemical modeling of enzymatic reactions : applications to the tautomerase superfamily

   Författare :Robin Sevastik; Fahmi Himo; Margaretha Blomberg; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bioengineering; Bioteknik;

   Sammanfattning : In this thesis, quantum chemical methods are used to investigate enzymatic reaction mechanisms. The Density functional theory, in particular the hybrid B3LYP functional, is used to model two enzymes belonging to the tautomerase superfamily; 4-Oxalocrotonate Tautomerase (4-OT) and cis-Chloroacrylic Acid Dehalogenase (cis-CAAD). LÄS MER

3. 2. 5-Aminolevulinic acid and derivatives thereof : properties, lipid permeability and enzymatic reactions

   Författare :Edvin Erdtman; Leif Eriksson; Tore Brinck; Örebro universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; 5-Aminolevulinic acid; tautomerization; PDT; DFT; MM; QM MM; Porphobilinogen synthase; Uroporphyrinogen III decarboxylase; membrane penetration; enzyme mechanism; Biophysical chemistry; Biofysikalisk kemi; Quantum chemistry; Kvantkemi; Theoretical chemistry; Teoretisk kemi; Fysikalisk kemi; Physical Chemistry; Biochemistry; Biokemi;

   Sammanfattning : 5-aminolevulinic acid (5-ALA) and derivatives thereof are widely usedprodrugs in treatment of pre-malignant skin diseases of the cancer treatmentmethod photodynamic therapy (PDT). The target molecule in 5-ALAPDTis protoporphyrin IX (PpIX), which is synthesized endogenously from5-ALA via the heme pathway in the cell. LÄS MER

4. 3. Dynamic Systems : Enzymatic Synthesis, Exchange Reactions and Applications in Materials Science

   Författare :Yang Zhang; Olof Ramström; Mihail D. Barboiu; KTH; []
   Nyckelord :constitutional dynamic chemistry; reversible reactions; kinetic resolution; dynamic kinetic resolution; enzyme catalysis; lipase; asymmetric synthesis; racemization; oxazolidinone; organogel; enamine; nitroaldol reaction.;

   Sammanfattning : This thesis is divided into three parts, revolving around the developments of dynamic systems utilized in dynamic kinetic resolution (DKR) and constitutional dynamic chemistry (CDC).The first section gives an introduction to constitutional dynamics, the core concept of this thesis. LÄS MER

5. 4. Quantum Chemical Modeling of Asymmetric Enzymatic Reactions

   Författare :Maria E. S. Lind; Fahmi Professor; Rajeev Prabhakar; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; biocatalysis; enantioselectivity; density functional theory; B3LYP; enzyme; hydrolysis; decarboxylation; Organic Chemistry; organisk kemi;

   Sammanfattning : Computational methods are very useful tools in the study of enzymatic reactions, as they can provide a detailed understanding of reaction mechanisms and the sources of various selectivities. In this thesis, density functional theory has been employed to examine four different enzymes of potential importance for biocatalytic applications. LÄS MER

7. 5. Quantum Chemical Cluster Modeling of Enzymatic Reactions

   Författare :Rongzhen Liao; Fahmi Himo; Robert Deeth; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cluster approach; density functional theory; B3LYP; enzyme; mechanism; dinuclear; trinuclear; zinc; tungsten; hydrolysis; decarboxylation; formaldehyde oxidation; hydration; methyl transfer; Quantum chemistry; Kvantkemi; organisk kemi; Organic Chemistry;

   Sammanfattning : The Quantum chemical cluster approach has been shown to be quite powerful and efficient in the modeling of enzyme active sites and reaction mechanisms. In this thesis, the reaction mechanisms of several enzymes have been investigated using the hybrid density functional B3LYP. LÄS MER