No description available.

No description available.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Missouri--Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves: 126-138). Also available on the Internet.

Doctor of Philosophy / Department of Chemistry / Duy H. Hua / Three research projects are described in this dissertation and they consist of the discovery of norovirus protease inhibitors, modification of graphene oxides (GO) for the detection of norovirus, and design and fabrication of nanoelectronic device based on nanocarbon fibers for the detection of breast cancer proteases, legumain and cathepsin B. A novel class of tripeptidyl anti-noroviral compounds which strongly inhibit NV3CL[superscript]pro in enzyme and cell based assays was discovered. An example of one of the most active compounds is (1-{3-methyl-1-[2-oxo-1-(2-oxo-pyrrolidin-3-ylmethyl)-ethylcarbamoyl]-butylcarbamoyl}-2-naphthalen-1-yl-ethyl)-carbamic acid benzyl ester, which showed an IC₅₀ value of 0.14 ± 0.2 μM (enzyme assay) and EC₅₀ value of 0.04 ± 0.02 μM (cell based assay). This compound has an aldehyde warhead, a P1 glutamine surrogate, a P2 leucine, a P3 L-1-napthylalanine and an N-terminal carboxybenzyl cap. The corresponding bisulfite adduct, 2-[2-(2-benzyloxycarbonylamino-3-naphthalen-1-yl-propionylamino)-4-methyl-pentanoylamino]-1-hydroxy-3-(2-oxo-pyrrolidin-3-yl)-propane-1-sulfonic acid monosodium salt, has a comparable activity in enzyme and cell based assays (IC₅₀ 0.24 ± 0.1 μM; EC₅₀ 0.04 ± 0.03 μM). (1-{3-methyl-1-[2-oxo-1-(2-oxo-pyrrolidin-3-ylmethyl)-ethylcarbamoyl]-butylcarbamoyl}-2-naphthalen-1-yl-ethyl)-carbamic acid benzyl ester and its ketoamide derivative, (1-{1-[2-isopropylcarbamoyl-2-oxo-1-(2-oxo-pyrrolidin-3-ylmethyl)-ethylcarbamoyl]-3-methyl-butylcarbamoyl}-2-naphthalen-1-yl-ethyl)-carbamic acid benzyl ester, exhibited very good broad spectrum anti-viral activity, especially in human rhino virus and severe acute respiratory syndrome bioassays. We demonstrated that the surface of graphene oxide can be chemically modified with t-butylester and carboxylic acid functionalities. Fourier transform infrared spectroscopy, Raman spectroscopy and solid state nuclear magnetic resonance spectroscopy confirmed the presence of t-butylester and carboxylic acid functional groups. One sided oligonucleotide functionalized graphene oxide was synthesized using a solid state technique. A carboxylic acid functionalized graphene oxide was deposited onto the surface of electronic chips to bridge two gold electrodes, using a direct deposition technique. The carboxylic acid functionalized graphene oxide displayed semi-conductive properties and its use in an electronic biosensor device to detect noroviral RNA was investigated. Novel redox-active protease substrate peptides H₂N-(CH₂)₄CO-Ala-Ala-Asn-Leu-NHCH₂-ferrocene and H₂N-(CH₂)₄CO-Leu-Arg-Phe-Gly-NHCH₂-ferrocene were synthesized successfully and used in an alternating current voltammetry technique to facilitate the detection of the cancer related protease enzymes legumain and cathepsin B. After attachment of these peptides to the tips of carbon nanofiber nanoelectrode arrays, the presence of active protease enzymes could be detected as manifest by an exponential decay in current signal detect when monitored by alternating current voltammetry, at initial enzyme concentrations of 80.1 nM (legumain) and 30.7 nM (cathepsin B). The peptide cleavage sites were confirmed by analyses of the cleaved fragments using high performance liquid chromatography and mass spectrometry. Results showed that the cleavage of H₂N-(CH₂)₄CO-Ala-Ala-Asn-Leu-NHCH₂-ferrocene at the C-terminal side of asparagine residues by legumain and cleavage of H₂N-(CH₂)₄CO-Leu-Arg-Phe-Gly-NHCH₂-ferrocene at the C-terminal side of arginine residues by cathepsin B. Legumain exhibited a specificity constant (k[subscript]cat/K[subscript]m) of 11.3 x 10ᶟ M⁻¹S⁻¹ while cathepsin B exhibited a higher value of specificity constant (4.3 x 10⁴ M⁻¹S⁻¹) which agreed with the values obtained from fluorescence enzyme assay.

No description available.

published_or_final_version / Pathology / Doctoral / Doctor of Philosophy

Class of 2007 Abstract / Objectives: To explore the effects of human immunodeficiency virus protease inhibitors (HPI) on insulin metabolism and protein degradation in HepG2 hepatocytes in vitro. Methods: To see if HIV-protease inhibitors affect insulin degradation in a dose-dependent manner, HepG2 cells were incubated with various concentrations of tipranavir, indinavir, or atazanavir. After 125I-insulin was added, its degradation was measured by precipitation with trichloroacetic acid (TCA). To see the effect of HPIs on protein degradation, HepG2 cells labeled overnight with 3H-leucine were incubated with 50 mM of an HPI, followed by another HPI incubation including concentrations of insulin ranging from 10-12 to 10-6 M. Cells were solubilized and proteins were precipitated using TCA. Degradation was quantified as percent TCA soluble, normalized, plotted, and then compared using student’s t-test or one- way ANOVA. Results: Cellular insulin degradation was inhibited only by tipranavir at the highest concentrations of 75 and 100 mM (12.06 ± 1.07%, p=0.047 and 9.35 ± 0.44%, p=0.024, respectively) when compared to the control (17.01 ± 1.37%; n=3). None of the concentrations of indinavir or atazanavir decreased insulin degradation significantly. From the protein degradation experiments, the log EC50 of the control (no HPI) insulin dose-response curve was not statistically different compared to those of the individual HPIs. Conclusions: Except for high concentrations of tipranavir, it appears that HPI does not inhibit the cellular degradation of insulin. HPIs do not appear to inhibit the role of insulin in the inhibition of protein degradation significantly.

Thesis (Ph. D.)--Georgia State University, 2007. / Title from file title page. Irene Weber, committee chair; John Houghton, Giovanni Gadda, committee members. Electronic text (186 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Dec. 20, 2007. Includes bibliographical references (p. 166-180).

Thesis (Ph.D.)--Baylor University, 2005. / Includes bibliographical references (p. 483-494).