Thesis (Ph.D. in Pharmaceutical Sciences) -- University of Colorado, 2006. / Typescript. Includes bibliographical references (leaves 144-161). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;

Magister Scientiae - MSc (Biotechnology) / Breast cancer is regarded as the most common form of cancer in women and it comprises of approximately 23 % of female cancers, while affecting women at any age range. For oestrogen receptor positive patients, tamoxifen is used as a prescribed medication for breast cancer therapy. However, tamoxifen in its natural form is not active to achieve the required treatment and prevention of breast cells proliferation. Since tamoxifen is a prodrug, it need to be converted into its active form, endoxifen, for which it is achieved by the action of the cytochrome P450 enzymes. Cytochrome P450 2D6 (CYP2D6) is a member of cytochrome P450 enzymes for which are superfamily of heme enzymes characterised by their ability to catalyse the oxidative reactions of compounds, including the pathway of tamoxifen metabolism. However, due to polymorphism that lead to inactive phenotypes of CYP2D6 in this gene, there is a challenge of diagnosing if a patient can metabolise tamoxifen or not. The current diagnostic tool, Amplichip CYP450, for CYP2D6 is based on genotypes, and it lead to uncertainness as to whether the presence of functionalCYP2D6 alleles of CYP2D6 may lead to coding of active protein, thus leading to wrong treatment measures and overdose of tamoxifen. Electrochemical techniques have provided reliable, simple, quick, and sensitive methods for the determination of drug metabolism by enzymes. Therefore, it is important to develop a CYP2D6 phenotype-based sensor to detect and tell whether a particular individual can metabolise the drug or not.

Les interactions protéine-ligand interviennent dans de nombreux processus biochimiques et permettent notamment à certaines protéines sanguines d’assurer leur rôle de transport. Parmi ces protéines figurent notamment l’albumine, protéine la plus abondante du plasma, ou l’apolipoprotéine A1 (ApoA1), majoritaire au sein des lipoprotéines de haute densité (HDL). Dans un contexte diabétique, la glycation des protéines induit des modifications structurales affectant ainsi leur potentiel d’interaction.Le premier objectif de ce travail de thèse visait à déterminer l’impact de la glycation de l’albumine sur sa liaison au liraglutide, un médicament de plus en plus utilisé dans le traitement du diabète de type 2. Ensuite, la seconde partie de ce travail a consisté en la production d’une ApoA1 humaine recombinante fonctionnelle afin d’étudier ses propriétés d’interaction, sous forme libre ou associée aux phospholipides. La technique RMN (résonance magnétique nucléaire) a été utilisée sur les protéines préalablement marquées au fluor (pour le liraglutide) ou aux isotopes stables 13C/15N (pour l’ApoA1). La titration microcalorimétrique isotherme (ITC), méthode complémentaire à la RMN a été appliquée pour l’étude des interactions avec l’avantage de ne nécessiter aucun marquage. Différentes stratégies de clonage ont été explorées pour la surexpression de l’ApoA1 en bactérie Clearcoli.Les résultats obtenus démontrent une altération de l’affinité de l’albumine pour le liraglutide in vitro et in vivo, dépendante du degré de glycation. Ces résultats, enrichis d’une analyse lipidomique et peptidique, permettent d’expliquer les observations cliniques concernant la baisse de l’efficacité de médicaments liant l’albumine chez les patients ayant un diabète mal contrôlé. Concernant l’ApoA1, le choix de l’étiquette de fusion reste à optimiser, mais sa surexpression de manière soluble et abondante a été obtenue pour l’ApoA1 marquée et non marquée. / Protein-ligand interactions are involved in many biochemical processes. They are notably implicated in the role of transporter proteins in blood. Albumin, the most abundant plasma protein, and apolipoprotein A1 (ApoA1), which is the main component of high-density lipoprotein (HDL) belong to this class of proteins. In the context of diabetes, proteins are altered by glycation which leads to structural modifications and potentially affect their interactions.The first objective of this work was to determine the impact of albumin glycation on its binding to liraglutide, a drug increasingly used in the treatment of type 2 diabetes. Then, the second part of this work involved the production of recombinant functional human ApoA1 in order to study its interaction properties, in its lipid-free form or associated with phospholipids. The NMR (nuclear magnetic resonance) technique has been used on proteins previously labeled with fluorine (for liraglutide) or stable 13C/15N isotopes (for ApoA1). In addition, isothermal titration microcalorimetry (ITC), has been applied to the study of interactions with the advantage of not requiring any labeling. Various cloning strategies have been explored for the overexpression of ApoA1 in Clearcoli bacteria.The results demonstrate an alteration of the affinity of albumin for liraglutide in vitro and in vivo, depending on the degree of glycation. These results, supported by a lipidomic and peptide analysis, explain clinical observations concerning the decrease of efficacy of albumin-binding drugs in patients with poorly controlled diabetes. Regarding ApoA1, the choice of the fusion tag remains to be optimized, but both labeled and unlabeled ApoA1 were successfully overexpressed at high yields in a soluble form.

Foi feita a caracterização eletroquímica do aço inoxidável austenítico UNS S31254 em meio de NaCl 0,11 mol L-1 na ausência e presença de soro albumina bovina (BSA) visando seu emprego em implantes ortopédicos. Foram empregadas como técnicas: medidas de potencial de circuito aberto, curvas de polarização, cronoamperometria, EIE, XPS, MEV, EDS e EEO. O comportamento eletroquímico do aço 254 foi comparado com o de outros aços empregados em implantes ortopédicos (ISO 5832-9, ASTM F138, e AISI 316L) na ausência e presença de BSA. O aço 254 se mostrou semelhante ao ISO 5832-9: encontra-se passivado desde o potencial de corrosão até o de transpassivação; a presença de inclusões de óxidos de cálcio e alumínio no aço 254 foi considerada a responsável por um potencial de transpassivação 100 mV menos positivo do que o observado com o aço ISO 5832-9. Foi detectada. além de óxido de Cr(III), a presença de Mo na forma Mo(VI) no filme passivo do aço 254. A ação da BSA, ora passivante ora catalisadora, depende de sua concentração, da natureza do substrato metálico, e do potencial na interfase metal-solução. A BSA modifica o mecanismo de oxidação do aço 254 e inibe seletivamente a dissolução dos seus elementos constituintes, em particular, níquel e cromo. / The electrochemical characterization of UNS S31254 has been made in 0.11 mol L-1 NaCl medium in the absence and presence of bovine serum albumin (BSA) in order to propose its application in orthopaedic implants. The techniques employed were: open circuit potential measurements, polarization curves, chronoamperometry, EIS, XPS, SEM, EDS and EEO. The electrochemical behavior of 254 SS was compared to that observed for ISO 5832-9, ASTM F138 and AISI 316L stainless steels, used in orthopedic implants, in the absence and presence of BSA. 254 SS is similar to ISO 5832-9 SS: it is passivated on the potential range between the corrosion and the transpassivation potentials; the presence of calcium and aluminum oxides can be responsible for the shift of about 100 mV to less positive potentials on the transpassivation potential when compared to ISO 5832-9 SS. The presence of Mo(VI) was detected beside Cr(III) as passivating film for 254 SS. BSA action depends on its concentration, the nature of the metallic substract and on the potential in the metal-solution interphase. BSA changes the oxidation mechanism of 254 SS and promotes the selective dissolution of the elements particularly nickel and chromium.

Submitted by CINTIA RAMOS CAMARGO null (cintiaramoscamargo@gmail.com) on 2017-10-26T19:26:25Z No. of bitstreams: 1 Tese _Cintia Ramos Camargo_.pdf: 5811868 bytes, checksum: a56e37c6cc9f843250f31549c5aa7e98 (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-10-31T18:52:56Z (GMT) No. of bitstreams: 1 camargo_cr_dr_sjrp.pdf: 5811868 bytes, checksum: a56e37c6cc9f843250f31549c5aa7e98 (MD5) / Made available in DSpace on 2017-10-31T18:52:56Z (GMT). No. of bitstreams: 1 camargo_cr_dr_sjrp.pdf: 5811868 bytes, checksum: a56e37c6cc9f843250f31549c5aa7e98 (MD5) Previous issue date: 2017-09-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A folha de louro verde brasileira, uma especiaria muito apreciada na cozinha local (Aniba riparia, Lauraceae), contém compostos químicos que apresentam derivados de benzoíla chamados riparinas, que possuem propriedades anti-inflamatórias, antimicrobianas e ansiolíticas. No entanto, não está claro qual o tipo de interação que as riparins desempenham com qualquer alvo molecular. Como um alvo rentável, a albumina de soro humano (HSA) é uma das principais proteínas extracelulares, com uma capacidade excepcional para interagir com várias moléculas, e também desempenha um papel crucial no transporte, distribuição e metabolismo de uma grande variedade de ligantes endógenos e exógenos. Para delinear o mecanismo de interação HSA-riparina, a espectroscopia e os métodos computacionais foram aplicados de forma sinérgica. Uma avaliação através de espectroscopia de fluorescência mostrou que a emissão, atribuída ao Trp 214, a 346 nm, diminuiu com as titulações das riparinas. Observou-se um mecanismo de supressão estática na ligação das riparinas à HSA. Os experimentos de fluorescência realizados em 298, 308 e 318 K possibilitaram a realização de análises termodinâmicas que indicassem uma reação espontânea na formação do complexo (ΔG <0). O experimento do balanço entálpico-entrópico e com um cálculo de modelagem molecular revelou que interações hidrofóbicas, ligação de hidrogênio e interações não específicas estão presentes para as riparinas I - III com a HSA. O conjunto de resultados das mudanças da fração de fluorescência obtidos através de Schatchard não foi conclusivo ao estabelecer que tipo de cooperatividade esteja presente na interação. Para esclarecer o complexo HSA-riparinas, a abordagem de Hill foi utilizada para distinguir o índice de afinidade e a constante de ligação. Observou-se uma correspondência entre as estruturas moleculares das riparinas, devido à presença do grupo hidroxila no anel B, com parâmetros termodinâmicos e índice de afinidade. Riparin III realiza uma ligação de hidrogênio intramolecular, que afeta o coeficiente de Hill e a constante de ligação. Portanto, a presença de grupos hidroxila é capaz de modular a interação entre riparinas e HSA. Os experimentos de competição de sítio indicaram o sítio I como sendo o mais acessado, e as ferramentas de modelagem molecular reforçavam os resultados experimentais detalhando a participação de resíduos. / The green Brazilian bay leaf, a spice much prized in local cuisine (Aniba riparia, Lauraceae), contains chemical compounds presenting benzoyl-derivatives named riparins, which have anti-inflammatory, antimicrobial and anxiolytic properties However, it is unclear what kind of interaction riparins perform with any molecular target. As a profitable target, human serum albumin (HSA) is one of the principal extracellular proteins, with an exceptional capacity to interact with several molecules, and it also plays a crucial role in the transport, distribution, and metabolism of a wide variety of endogenous and exogenous ligands. To outline the HSA– riparin interaction mechanism, spectroscopy and computational methods were synergistically applied. An evaluation through fluorescence spectroscopy showed that the emission, attributed to Trp 214, at 346 nm decreased with titrations of riparins. A static quenching mechanism was observed in the binding of riparins to HSA. Fluorescence experiments performed at 298, 308 and 318 K made it possible to conduct thermodynamic analysis indicating a spontaneous reaction in the complex formation (ΔG<0). The enthalpy-entropy balance experiment with a molecular modeling calculation revealed that hydrophobic, hydrogen bond and non-specific interactions are present for riparin I - III with HSA. The set of results from fractional fluorescence changes obtained through Schatchard was inconclusive in establishing what kind of cooperativity is present in the interaction. To shed light upon the HSA-riparins complex, Hill’s approach was utilized to distinguish the index of affinity and the binding constant. A correspondence between the molecular structures of riparins, due to the presence of the hydroxyl group in the B-ring, with thermodynamic parameters and index of affinity were observed. Riparin III performs an intramolecular hydrogen bond, which affects the Hill coefficient and the binding constant. Therefore, the presence of hydroxyl groups is capable of modulating the interaction between riparins and HSA. Site marker competitive experiments indicated Site I as being the most suitable, and the molecular modeling tools reinforced the experimental results detailing the participation of residues.

Este trabalho tem como objetivo sintetizar e caracterizar um novo complexo mononuclear de rutênio (III) e enrofloxacina (enro, fármaco antibacteriano da família das fluoroquinolonas), [Ru(enro)3].nH2O. Foram testadas várias rotas sintéticas e apenas a partir de uma delas obteve-se o composto desejado. O produto foi caracterizado pelas técnicas espectroscópicas de absorção na região do UV-visível e do infra-vermelho. Através desta última técnica foi possível determinar o modo pelo qual a enrofloxacina se coordena ao íon rutênio: a coordenação ocorre de modo bidentado através do oxigênio da piridona e do oxigênio do grupamento carboxilato. Outro objetivo deste trabalho foi investigar a interação do complexo mononuclear de rutênio (III) e norfloxacina, [Ru(nor)3].nH2O, com a albumina de soro humano (HSA), através da técnica de luminescência. Mais especificamente pelo estudo da supressão da luminescência dos resíduos de triptofano, aplicando-se o modelo de tratamento da supressão bimolecular de Stern-Volmer. O estudo de supressão de fluorescência mostrou, por meio de espectros de emissão da HSA, que com o aumento da concentração do complexo [Ru(nor)3].nH2O na solução de HSA, ocorre uma redução gradual da luminescência da HSA, devido a alterações da conformação da proteína, que sugerem alteração do microambiente próximos aos resíduos de triptofano. A partir do tratamento dos dados pode-se determinar tanto K_sv quanto a constante cinética do processo de supressão, que mostraram uma dependência com a temperatura sugerindo como mecanismo predominante de supressão o mecanismo dinâmico. Porém essa conclusão foi revista a partir da determinação dos tempos de vida do estado excitado da HSA, e pode-se concluir que o mecanismo predominante à temperatura ambiente é o mecanismo estático, porém com o aumento da temperatura ocorre a predominância do mecanismo do tipo dinâmico. Através da determinação dos parâmetros termodinâmicos, concluiu-se que as interações entre a HSA e o complexo são espontâneas, e forças de van der Waals e ligações de hidrogênio estão envolvidas na ligação entre a HSA e o supressor. / This work aims to synthesize and characterize a new mononuclear ruthenium (III) complex and enrofloxacin (enro, antibacterial drug of the fluoroquinolone family), [Ru(enro)3].nH2O. Several synthetic routes were tested, but only from one of them it was obtained the desired compound. The product was characterized by spectroscopic techniques of absorption in UV-visible and infra-red regions. Through this last technique, it was possible to determine the coordination mode of enrofloxacin to the ruthenium ion: the coordination occurs in a bidentate way through the pyridone oxygen and the oxygen of the carboxylate group. Another aim of this study was to investigate the interaction of mononuclear ruthenium (III) complex and the norfloxacin, [Ru(nor)3].nH2O, with the human serum albumin (HSA), through the technique of luminescence. More specifically, by the study of the quenching of luminescence of tryptophan residues, by applying the Stern-Volmers model of treatment of bimolecular suppression. The fluorescence quenching study showed, through the emission spectra of HSA, that increasing the complex concentration in HSA solution, there is a gradual reduction of the luminescence of HSA, due to the conformational changes of the protein that suggests the change of microenvironment near tryptophan residues. From the data processing it is possible to determine both K_sv and the kinetic constant of the suppression process, which showed temperature dependence, suggesting as the predominant mechanism of quenching the dynamic mechanism. However, this conclusion has been revised from the determination of the lifetimes of the excited state of HSA, and it can be concluded that the predominant mechanism at room temperature is the static mechanism, but with the temperatures increase, it occurs the predominance of the dynamic type mechanism. By determining the thermodynamic parameters, it was concluded that the interactions between HSA and the complex are spontaneous, and Van der Waals forces and hydrogen bonds are involved in the binding between HSA and suppressor.

A interface formada por materiais biológicos e materiais sintéticos tem grande importância em aplicações biomédicas, tais como o desenvolvimento de biomateriais para implantes médicos, que tem como processo essencial a deposição de proteínas na superfície dos biomateriais, e ainda não é bem compreendido no nível molecular. Algumas proteínas sofrem mudanças conformacionais após a adsorção na interface sólido-líquido, afetando suas funções ou propriedades, e algumas técnicas podem medir mudanças conformacionais em interfaces sólido. É possível estudar a fluorescência intrínseca de proteínas: a posição do máximo na faixa espectral da fluorescência, a eficiência quântica e o tempo de vida de fluorescência são indicadores de mudanças no ambiente local de grupos de moléculas de proteína fluorescente. Por outro lado, Nanopartículas de ouro têm atraído muita atenção pela sua afinidade com materiais biológicos e suas propriedades ópticas. Nesta tese, estudamos a viabilidade de substratos de vidro, quartzo, mica e ITO (óxido de índio e estanho) modificado com quitosana, phtalocyanines (Ni, Fe e Ni) e poli(alilanina hidroclorada) (PAH) na adsorção de BSA em forma dos filmes produzidos pela técnica camada por camada. O sistema foi estudado por UV-Vis e espectroscopia de fluorescência estática e resolvida no tempo. A caracterização morfológica dos filmes foi realizada por microscopia de força atômica e microscopia óptica. Os resultados mostram que os filmes de BSA / HAP cresceram com eficiência quatro vezes maior do que os filmes feitos de quitosana, que o quartzo tem a melhor janela de trabalho de UV-vis e há uma relação entre o pH da BSA e o tempo vida de fluorescência do filme resultante. As nanopartículas de ouro foram produzidas pela redução química e estabilizada por quatro diferentes métodos. O crescimento das nanopartículas foi monitorado por UV-vis spectroscopy. A carga de superfície das nanopartículas e da BSA foi estimado em vários valores de pH por medidas de potencial zeta. Os resultados indicaram que as nanopartículas têm cargas negativas na faixa de pH estudada. Soluções de BSA foram preparadas em diferentes valores de pH, e levadas para interagir com as nanopartículas de ouro. Os dados de supressão de fluorescência da BSA mostraram uma maior afinidade da BSA com nanopartículas estabilizadas com sacarose, com pH próximo do ponto isoelétrico (IP) estimado para BSA. / The interface formed by biological materials and synthetic materials has great importance in biomedical applications such as the development of biomaterials for medical implants, which has as an essential process of protein adsorption on the surface of biomaterials, and is not yet well understood in the molecular level. Some proteins undergo conformational changes after adsorption at solid-liquid interfaces, affecting their functions or properties, and few techniques can measure conformational changes in solid interfaces. It is possible to study the intrinsic fluorescence of proteins: the position of the maximum in the spectral range of fluorescence, the quantum efficiency and lifetime of fluorescence are indicators of change in the local environment of fluorescent groups of protein molecules. On the other hand, gold nanopartículas have attracted much attention for its affinity with biological materials and their optical properties. In this thesis we study the feasibility of glass substrates, quartz, mica and ITO (Indium tin oxide) modified with chitosan, phtalocyanines (Ni, Fe and Ni) and poly (allylamine hydrochloride) (PAH) on the adsorption of BSA in the form of films produced by the layer by layer technique. The system was studied by UV-Vis and static and time-resolved fluorescence spectroscopy. Morphological characterization of the films was performed by atomic force microscopy and optical microscopy. The results indicate that the films of BSA/PAH grew with efficiency four times greater than the films made of chitosan, that the quartz has the best working window for UV-vis and there is a relationship between the pH of the BSA and lifetime of fluorescence of the resulting film. Gold nanoparticles were produced by chemical reduction and stabilized by four different methods. The growth of nanoparticles was monitored by UV-vis spectroscopy. The surface charge of nanoparticles and the BSA was estimated at various pH values by zeta potential measurements. The results indicated that the nanoparticles have negative charges in the pH range studied. BSA solutions were prepared at various pH values, were taken to interact with gold nanoparticles. Fluorescence quenching data of BSA showed a greater affinity of the BSA with nanoparticles stabilized with sucrose, at pH near the isoelectric point (IEP) estimated for BSA.

Masters of Science / Invasive pneumococcal disease (IPD), which includes potentially fatal conditions such as meningitis, septicaemia and pneumonia poses a threat in children aged <5 years, pneumonia being the leading cause of child mortality worldwide. Even though capsular polysaccharides are the main antigens involved in the immunity to encapsulated bacteria, it was found that in children in that age group, the immune system was unresponsive. Conjugate vaccines however induce immunologic memory and provide long-term protective immunity. Therefore the aim of this project was to develop novel conjugation strategies towards a pneumococcal conjugate vaccines and focuses mainly on the serotypes that are a burden to the African continent. The chemistry involved in developing a conjugate vaccine is of importance beacuse while some polysaccharides contain chemical grouping which can be conveniently utilized for conjugation, many medically important ones require derivatization before they can be coupled to protein. Derivatization of which can be achieved through various strategies, important to note is through hypervalent iodine oxidants. Two hypervalent iodine reagents, O-Methyl substituted-1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (Me-IBX)and modified 1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (mIBX)were successfully synthesized in preparation for the use in polysaccharide, polyribitol phosphate, (PRP) oxidation. The polysaccharide to be oxidised was first size reduced by microfluidisation to allow maximum oxidation. However, the extent to which oxidisation was achieved was not enough to conjugate the polysaccharide to the protein of preference, Bovine Serum Albumin, (BSA).

In this study the heat-induced gelation of two (readily available) proteins, which contain disulphide bonds, has been investigated over a range of protein concentrations in the presence and absence of the presence of the reductant, dithiothreitol at neutral pH. The proteins selected in this study were: β-Lactoglobulin and bovine serum albumin. These proteins have different number of disulphide bonds and possess different protein secondary structures. The influences of the reductant and protein concentration on their heat-induced gelation were explored to see whether the proteins were able to form protein hydrogels and that the mechanical properties of the resulting protein hydrogels were controllable. The tilting test tube method revealed that both proteins formed macroscopic hydrogels, at protein concentrations above the critical gelation concentration and that the critical gelation concentration was constantly lower in the presence of the reductant. Micro-DSC revealed that both proteins had completely denatured upon heating and that the denaturation temperature and enthalpy were significantly lower in the presence of the reductant. IR spectroscopy revealed that both proteins undergo major secondary structure transitions that resulted in the formation of fibers that are rich in β-sheet structure upon heating and that the protein lost some secondary structure before any heating and gained more β-sheet structure in the presence of the reductant. Both proteins had partially denatured before any heating in the presence of the reductant and that β-LG underwent aggregation that was accompanied by the loss of native β-sheet structure and the formation of intermolecular β-sheet structure, while that BSA underwent aggregation that was accompanied by the loss of native α-helix structure and the formation of intermolecular β-sheet structure. Cryo-TEM revealed that both proteins formed fibers (10 nm in diameter) that exist as single entities at low protein concentrations and become entangled into macroscopic networks, at protein concentrations above the critical gelation concentration and that more fibers and denser macroscopic networks were formed in the presence of the reductant. Oscillatory rheology revealed that both proteins formed macroscopic networks exhibit viscoelastic behaviour and that their elastic modulus had increased in the presence of the reductant and with increasing protein concentration.

The potential use of polymeric, functionalized nanoparticles (NPs) as drug delivery vectors was explored. Covalent conjugation of albumin to the surface of NPs via maleimide chemistry proved problematic. However, microwave assisted synthesis of NPs was not only time efficient, but enabled the exploration of size control by changing the following parameters: temperature, microwave power, reaction time, initiator concentration, and percentage of monomer used. About 1.5 g of fluorescently-labeled, carboxylic acid-functionalized NPs (100 nm diameter) were synthesized for a total cost of less than $1. Future work will address further functionalization of the NPs for the coupling of albumin (or other targeted proteins), and tests for in vivo biodistribution.