Transition state analysis of thymidine phosphorylase from E. coli.
Transition state analysis of thymidine phosphorylase from E. coli.
dc.contributor.author | Rezaei, Mansoureh | en_US |
dc.contributor.department | Chemistry | en_US |
dc.date.accessioned | 2014-06-20T17:39:22Z | |
dc.date.available | 2014-06-20T17:39:22Z | |
dc.date.issued | 2001 | en_US |
dc.description.abstract | Thymidine phosphorylase (E.C. 2.4.2.4) (TP) is an enzyme involved in the reversible conversion of thymidine, deoxyuridine, and their analogs to their respective bases and 2-alpha-D-deoxyribose-1-phosphate. This enzyme is identical to an angiogenic factor, platelet-derived endothelial cell growth factor. TP is expressed at high levels in a wide variety of solid tumors and is known to promote the development of new blood vessels, which are fundamental to tumor growth and metastasis. | en_US |
dc.description.abstract | The transition state of thymidine phosphorylase has been characterized by kinetic isotope effects, bond-energy bond-order vibrational analysis, and molecular electrostatic potential surface and quantum chemical calculations. Kinetic isotope effects for arsenolysis were measured by liquid chromatography/mass spectrometry for [1'-2H], [2' -2H], [5'-2H], [1'-13C], [2' -13C), and [1-15N] uridine to provide experimental values of 1.144 +/- 0.050, 0.959 +/- 0.012, 0.988 +/- 0.127, 1.013 +/- 0.007, 0.995 +/- 0.002, and 1.027 +/- 0.046 respectively. These kinetic isotope effects were matched to a geometric transition state model selected by bond-energy bond-order vibrational analysis (BEBOVIB-IV program). | en_US |
dc.description.abstract | The transition state can be described as an SN1 type reaction with oxocarbenium ion character with slight hyperconjugation existing between the C2'-H2' and C1'-N1 bonds, and C4 '-endo and C3'- exo conformation of furanose ring due to protonation of O2 in the uracil ring. Protonation of O2 also assists departure of the uracil. From the BEBOVIB-IV calculations, the 13C isotope effect predicts a bond order of 0.78 for C1'-N 1, indicating an early transition state. | en_US |
dc.description.abstract | Inhibitor design for thymidine phosphorylase was attempted by incorporating features of the transition state. | en_US |
dc.description.degree | D.A. | en_US |
dc.identifier.uri | http://jewlscholar.mtsu.edu/handle/mtsu/4058 | |
dc.publisher | Middle Tennessee State University | en_US |
dc.subject.lcsh | Chemistry, Biochemistry | en_US |
dc.subject.lcsh | Chemistry, Physical | en_US |
dc.thesis.degreegrantor | Middle Tennessee State University | en_US |
dc.thesis.degreelevel | Doctoral | en_US |
dc.title | Transition state analysis of thymidine phosphorylase from E. coli. | en_US |
dc.type | Dissertation | en_US |
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