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Dissertations / Theses on the topic 'Pyrimidine nucleotides'

Author: Grafiati

Published: 4 June 2021

Last updated: 21 February 2023

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1

Eguae, Samuel Iyamu. "Pyrimidine nucleotide metabolism in Rhizobium meliloti: purification of aspartate transcarbamoylase from a pyrimidine auxotroph." Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc332674/.

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Rhizobium aspartate transcarbamoylase (ATCase; EC 2.1.3.2) was previously believed to be similar to the Pseudomonas ATCase which has been studied extensively. To facilitate the study of the Rhizobium ATCase a pyrimidine-requiring mutant of R. meliloti was isolated and used in the purification of the enzyme.

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2

Stewart, John E. B. (John Edward Bakos). "Characterization of Aspartate Transcarbamoylase in the Archaebacterium Methanococcus Jannaschii." Thesis, University of North Texas, 1996. https://digital.library.unt.edu/ark:/67531/metadc935724/.

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Asparate transcarbamoylase catalyzes the first committed step in the de novo synthesis of pyrmidine nucleotides UMP, UDP, UTP, and CTP. The archetype enzyme found in Escherichia coli (310 kDa) exhibits sigmodial substrate binding kinetics with positive control by ATP and negative control with CTP and UTP. The ATCase characterized in this study is from the extreme thermophilic Archaebacterium, Methanococcus jannaschii. The enzyme was very stable at elevated temperatures and possessed activity from 20 degrees Celsius to 90 degrees Celsius. M. Jannaschii ATCase retained 75% of its activity after

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3

So, Ngar-chung Nellie. "Pyrimidine nucleotide biosynthesis in adult angiostrongylus Cantonensis (Nematoda : Metastrongyloidea) /." [Hong Kong : University of Hong Kong], 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13637745.

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4

蘇雅頌 and Ngar-chung Nellie So. "Pyrimidine nucleotide biosynthesis in adult angiostrongylus Cantonensis (Nematoda : Metastrongyloidea)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B3123320X.

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5

Brichta, Dayna Michelle. "Construction of a Pseudomonas aeruginosa Dihydroorotase Mutant and the Discovery of a Novel Link between Pyrimidine Biosynthetic Intermediates and the Ability to Produce Virulence Factors." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4344/.

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The ability to synthesize pyrimidine nucleotides is essential for most organisms. Pyrimidines are required for RNA and DNA synthesis, as well as cell wall synthesis and the metabolism of certain carbohydrates. Recent findings, however, indicate that the pyrimidine biosynthetic pathway and its intermediates maybe more important for bacterial metabolism than originally thought. Maksimova et al., 1994, reported that a P. putida M, pyrimidine auxotroph in the third step of the pathway, dihydroorotase (DHOase), failed to produce the siderophore pyoverdin. We created a PAO1 DHOase pyrimidine auxotr

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6

Entezampour, Mohammad. "Characterization of pyrimidine biosynthesis in Acinetobacter calcoaceticus using wild type and mutant strains." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc798038/.

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Pyrimidine nucleotide biosynthesis was studies in Acinetobacter calcoaceticus ADP-1. Pyrimidine auxotrophic mutants were isolated and characterized for this purpose. One such Pyr mutant, strain ADP-1-218 was chosen for further study.

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7

Vickrey, John F. (John Fredrick) 1959. "Isolation and Characterization of the Operon Containing Aspartate Transcarbamoylase and Dihydroorotase from Pseudomonas aeruginosa." Thesis, University of North Texas, 1993. https://digital.library.unt.edu/ark:/67531/metadc278859/.

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The Pseudomonas aeruginosa ATCase was cloned and sequenced to determine the correct size, subunit composition and architecture of this pivotal enzyme in pyrimidine biosynthesis. During the course of this work, it was determined that the ATCase of Pseudomonas was not 360,000 Da but rather present in a complex of 484,000 Da consisting of two different polypeptides (36,000 Da and 44,000 Da) with an architecture similar to that of E. coli ATCase, 2(C3):3(r2). However, there was no regulatory polypeptide found in the Pseudomonas ATCase.

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8

AsFour, Hani. "Effector Response of the Aspartate Transcarbamoylase From Wild Type Pseudomonas Putida and a Mutant with 11 Amino Acids Deleted at the N-terminus of PyrB." Thesis, University of North Texas, 2002. https://digital.library.unt.edu/ark:/67531/metadc3163/.

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Like its enteric counterpart, aspartate transcarbamoylase (ATCase) from Pseudomonas putida is a dodecamer of two different polypeptides. Unlike the enterics, the Pseudomonas ATCase lacks regulatory polypeptides but employs instead inactive dihydroorotases for an active dodecamer. Previous work showed that PyrB contains not only the active site but also the effector binding sites for ATP, UTP and CTP at its N-terminus. In this work, 11 amino acids were deleted from the N-terminus of PyrB and the ATCase with the truncated protein was expressed in E. coli pyrB- and purified. The wild type enzym

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9

Kumar, Alan P. "Structure-Function Studies on Aspartate Transcarbamoylase and Regulation of Pyrimidine Biosynthesis by a Positive Activator Protein, PyrR in Pseudomonas putida." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4362/.

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The regulation of pyrimidine biosynthesis was studied in Pseudomonas putida. The biosynthetic and salvage pathways provide pyrimidine nucleotides for RNA, DNA, cell membrane and cell wall biosynthesis. Pyrimidine metabolism is intensely studied because many of its enzymes are targets for chemotheraphy. Four aspects of pyrimidine regulation are described in this dissertation. Chapter I compares the salvage pathways of Escherichia coli and P. putida. Surprisingly, P. putida lacks several salvage enzymes including nucleoside kinases, uridine phosphorylase and cytidine deaminase. Without a funct

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10

Hammerstein, Heidi Carol. "Isolation of a Pseudomonas aeruginosa Aspartate Transcarbamoylase Mutant and the Investigation of Its Growth Characteristics, Pyrimidine Biosynthetic Enzyme Activities, and Virulence Factor Production." Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4704/.

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The pyrimidine biosynthetic pathway is an essential pathway for most organisms. Previous research on the pyrimidine pathway in Pseudomonas aeruginosa (PAO1) has shown that a block in the third step of the pathway resulted in both a requirement for exogenous pyrimidines and decreased ability to produce virulence factors. In this work an organism with a mutation in the second step of the pathway, aspartate transcarbamoylase (ATCase), was created. Assays for pyrimidine intermediates, and virulence factors were performed. Results showed that the production of pigments, haemolysin, and rhamnoli

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11

Ruley, Jill R. (Jill Rosanne). "Creation and characterization of an Escherichia coli and Pseudomonas putida hybrid aspartate transcarbamoylase." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc798137/.

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Aspartate transcarbamoylase (ATCase) is encoded by the pyrBI genes in E. coli. Expression of these genes is reduced four-fold by attenuation when grown on uracil. Using plasmid, pRO1727. the pyrB and the pyrBI genes from E. coli were cloned into a P. putida pyrB auxotroph. A recombinant pyrB gene was recovered that encoded a functional hybrid ATCase with a molecular weight of 470 kDa.

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12

Kim, Hyunju. "Multiple Activities of Aspartate Transcarbamoylase in Burkholderia cepacia: Requirement for an Active Dihydroorotase for Assembly into the Dodecameric Holoenzyme." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc33176/.

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The aspartate transcarbamoylase (ATCase) was purified from Burkholderia cepacia 25416. In the course of purification, three different ATCase activities appeared namely dodecameric 550 kDa holoenzyme, and two trimeric ATCases of 140 kDa (consists of 47 kDa PyrB subunits) and 120 kDa (consists of 40 kDa PyrB subunits) each. The 120 kDa PyrB polypeptide arose by specific cleavage of the PyrB polypeptide between Ser74 and Val75 creating an active polypeptide short by 74 amino acids. Both the 40 and 47 kDa polypeptides produced active trimers. To compare the enzyme activity of these trimers, an eff

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13

Fong, Yuen Ting. "Quantitative structure retention relationships on using high-performance liquid chromatography." HKBU Institutional Repository, 2003. http://repository.hkbu.edu.hk/etd_ra/426.

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14

Linscott, Andrea J. (Andrea Jane). "Regulatory Divergence of Aspartate Transcarbamoylase from the Pseudomonads." Thesis, University of North Texas, 1996. https://digital.library.unt.edu/ark:/67531/metadc277625/.

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Aspartate transcarbamoylase (ATCase) was purified from 16 selected bacterial species including existing Pseudomonas species and former species reassigned to new genera. An enormous diversity was seen among the 16 enzymes with each class of ATCase being represented. The smallest class, class C, with a catalytically active homotrimer, at 100 kDa, was found in Bacillus and other Gram positive bacteria. In this report, the ATCases from the Gram negatives, Shewanella putrefaciens and Stenotrophomonas maltophilia were added to class C membership. The enteric bacteria typify class B ATCases at 310 kD

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15

Barron, Vincent N. (Vincent Neal). "Comparison of Aspartate Transcarbamoylase and Pyrimidine Salvage in Sporosarcina urea, Sprolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc278938/.

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The enzyme that catalyzes the committed step in pyrimidine biosynthesis, aspartate transcarbamoylase, has been compared in selected endospore-forming organisms and in morphologically similar control organisms. The ATCases and pyrimidine salvage from Sporosarcina ureae, Sporolactobacillus inulinus, Lactobacillus fermentum, and Micrococcus luteus were compared to those of Bacillus subtilis. While the ATCases from Sporosarcina ureae, Sporolactobacillus inulinus, and L. fermentum were found to exhibit characteristics to that of Bacillus with respect to molecular weight and kinetics, M. luteus ATCa

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16

Hongsthong, Apiradee 1970. "Assembly of Pseudomonas putida Aspartate Transcarbamoylase and Possible Roles of the PyrC' Polypeptide in the Folding of the Dodecameric Enzyme." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc278618/.

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Aspartate transcarbamoylase (ATCase) of Pseudomonas putida consists of two different polypeptides, PyrB and PyrC' (Schurr et al, 1995). The role of the PyrC' and the assembly of PyrB and PyrC' have been studied. The ATCase made in vitro of P.putida PyrB with P.putida PyrC', and of E.coli PyrB with P.putida PyrC ' were generated under two different conditions, denaturation and renaturation, and untreated. It was found that PyrC' plays a role in the enzymatic regulation by ATP, CTP and UTP. In addition to playing a role in substrate binding, the PyrB polypeptide is also involved in effector bi

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17

Dill, Michael T. "Characterization of the Aspartate Transcarbamoylase that is Found in the pyrBC Complex of Bordetella Pertussis." Thesis, University of North Texas, 2001. https://digital.library.unt.edu/ark:/67531/metadc3057/.

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An aspartate transcarbamoylase (ATCase) gene from Bordetella pertussis was amplified by PCR and ligated into pT-ADV for expression in Escherichia coli. This particular ATCase (pyrB) was an inactive gene found adjacent to an inactive dihydroorotase (DHOase) gene (pyrC'). This experiment was undertaken to determine whether this pyrB gene was capable of expression alone or if it was capable of expression only when cotransformed with a functional pyrC'. When transformed into E. coli TB2 pyrB-, the gene did not produce any ATCase activity. The gene was then co-transformed into E. coli TB2 p

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18

Kim, Seongcheol. "Purification and Characterization of Proteolytic Aspartate Transcarbamoylase (ATCase) from Burkholderia cepacia 25416 and Construction of a pyrB1 Knock-out Mutant." Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4694/.

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Burkholderia cepacia is a common soil bacterium of significance in agriculture and bioremediation. B. cepacia is also an opportunistic pathogen of humans causing highly communicable pulmonary infections in cystic fibrosis and immunocompromized patients. The pyrB gene encoding ATCase was cloned and ATCase was purified by the glutathione S-transferase gene fusion system. The ATCase in B. cepacia has been previously classified as a class A enzyme by Bethell and Jones. ATCase activity gels showed that B. cepacia contained a holoenzyme pyrBC complex of 550 kDa comprised of 47 kDa pyrB and 45 k

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19

Higginbotham, Leah. "Aspartate Transcarbamoylase of Aeromonas Hydrophila." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc5840/.

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This study focused on the enzyme, aspartate transcarbamoylase (ATCase) from A. hydrophila, a Gram-negative bacterium found in fresh water. The molecular mass of the ATCase holoenzyme from A. hydrophila is 310 kDa. The enzyme is likely composed of 6 catalytic polypeptides of 34 kDa each and 6 regulatory polypeptides of 17 kDa each. The velocity-substrate curve for A. hydrophila ATCase is sigmoidal for both aspartate and carbamoylphosphate. The Km for aspartate was the highest to date for an enteric bacterium at 97.18 mM. The Km for carbamoylphosphate was 1.18 mM. When heated to 60 ºC, the speci

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20

Hooshdaran, Massoumeh Ziba. "Comparative Biochemistry and Evolution of Aspartate Transcarbamoylase from Diverse Bacteria." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc500380/.

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Aspartate transcarbamoylase (ATCase) catalyzes the first committed step in pyrimidine biosynthesis. Bacterial ATCases are divided into three classes, A, B and C. Class A ATCases are largest at 450-500, are. dodecamers and represented by Pseudomonas ATCase. The overlapping pyrBC' genes encode the Pseudomonases ATCase, which is active only as a 480 kDa dodecamer and requires an inactive pyrC'-encoded DHOase for ATCase activity. ATCase has been studied in two non-pathogenic members of Mycobacterium, M. smegmatis and M. phlei. Their ATCases are dodecamers of molecular weight 480 kDa, composed of s

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21

Fields, Christopher J. "Comparative biochemistry and genetic analysis of nucleoside hydrolase in Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas fluorescens." Thesis, University of North Texas, 2002. https://digital.library.unt.edu/ark:/67531/metadc3290/.

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The pyrimidine salvage enzyme, nucleoside hydrolase, is catalyzes the irreversible hydrolysis of nucleosides into the free nucleic acid base and D-ribose. Nucleoside hydrolases have varying degrees of specificity towards purine and pyrimidine nucleosides. In E. coli, three genes were found that encode homologues of several known nucleoside hydrolases in protozoa. All three genes (designated yaaF, yeiK, and ybeK) were amplified by PCR and cloned. Two of the gene products (yeiK and ybeK) encode pyrimidine-specific nucleoside hydrolases, while the third (yaaF) encodes a nonspecific nucleoside hy

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22

Wei, Shuang. "Modifications du metabolisme des nucleotides en relation avec la differenciation et en reponse a une irradiation dans des cellules tumorales humaines (doctorat : structure et fontionnement des systemes biologiques integres)." Paris 11, 1998. http://www.theses.fr/1998PA114846.

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23

Hooshdaran, Sahar. "Characterization of Moraxella bovis Aspartate Transcarbamoylase." Thesis, University of North Texas, 2001. https://digital.library.unt.edu/ark:/67531/metadc3012/.

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Aspartate transcarbamoylase (ATCase) catalyzes the first committed step in the pyrimidine biosynthetic pathway. Bacterial ATCases have been divided into three classes, class A, B, and C, based on their molecular weight, holoenzyme architecture, and enzyme kinetics. Moraxella bovis is a fastidious organism, the etiologic agent of infectious bovine keratoconjunctivitis (IBK). The M. bovis ATCase was purified and characterized for the first time. It is a class A enzyme with a molecular mass of 480 to 520 kDa. It has a pH optimum of 9.5 and is stable at high temperatures. The ATCase holoenzyme i

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24

Patel, Seema R. "A Study of the Pyrimidine Biosynthesis Pathway and its Regulation in Two Distinct Organisms: Methanococcus jannaschii and Pseudomonas aeruginosa." Thesis, University of North Texas, 2001. https://digital.library.unt.edu/ark:/67531/metadc3038/.

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Methanococcus jannaschii is a thermophilic methane producing archaebacterium. In this organism genes encoding the aspartate transcarbamoylase (ATCase) catalytic (PyrB) and regulatory (PyrI) polypeptides were found. Unlike Escherichia coli where the above genes are expressed from a biscistronic operon the two genes in M. jannaschii are separated by 200-kb stretch of genome. Previous researchers have not been able to show regulation of the M. jannaschii enzyme by the nucleotide effectors ATP, CTP and UTP. In this research project we have genetically manipulated the M. jannaschii pyrI gene

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25

Schurr, Michael J. (Michael John). "Molecular and Kinetic Characterization of the Aspartate Transcarbamoylase Dihydroorotase Complex in Pseudomonas putida." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc277575/.

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Aerobic Gram negative bacteria such as Pseudomonas putida were reported to possess class A ATCases and to have a M.W. of 360 kD. The nucleotide sequence of the P. putida pyrBC was determined to answer this question once and for all. The expected regulatory gene was not found. It is shown that the P. putida pyrB gene is overlapped by pyrC by 4 bp. The P.putida pyrB is 1005 bp (335 aa) in length and the pyrC is 1275 bp (425 aa) long. Both of these genes complement E. coli mutants with their respective genotypes. Another finding borne out from the sequence is an effector binding site at the N-ter

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26

Fowler, Michael A. (Michael Allen) 1961. "Characterization of Aspartate Transcarbamoylase and Dihydroorotase in Moraxella Catarrhalis." Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc277709/.

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Bacterial aspartate transcarbamoylases (ATCase's) are divided into three classes that correspond to taxonomic relationships within the bacteria. The opportunistic pathogen Moraxeila catarrhalis has undergone several reclassifications based on traditional microbiological criteria. The previously uncharacterized ATCase from M. catarrhalis was purified to homogeneity and its chemical properties characterized. The ATCase from M. catarrhalis is a class C ATCase with an apparent molecular mass of 480-520 kDa. The M. catarrhalis ATCase is a dodecomer composed of six 35 kDa polypeptides and six 45 kDa

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27

Cooke, Patrick Alan. "BioInformatics, Phylogenetics, and Aspartate Transcarbamoylase." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2580/.

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In this research, the necessity of understanding and using bioinformatics is demonstrated using the enzyme aspartate transcarbamoylase (ATCase) as the model enzyme. The first portion of this research focuses on the use of bioinformatics. A partial sequence of the pyrB gene found in Enterococcus faecalis was submitted to GenBank and was analyzed against the contiguous sequence from its own genome project. A BLAST (Basic Local Alignment Search Tool; Atschul, et al., 1990) was performed in order to hypothesize the remaining portion of the gene from the contiguous sequence. This allowed a gl

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28

BAILLON, JEAN. "Les enzymes du metabolisme des nucleotides pyrimidiques comme cibles dans la chimiotherapie antitumorale." Paris 6, 1987. http://www.theses.fr/1987PA066118.

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29

Stawska, Agnieszka A. "Purification of Aspartate Transcarbamoylase from Moraxella (Branhamella) catarrhalis." Thesis, University of North Texas, 2001. https://digital.library.unt.edu/ark:/67531/metadc2864/.

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The enzyme, aspartate transcarbamoylase (ATCase) from Moraxella (Branhamella) catarrhalis, has been purified. The holoenzyme has a molecular mass of approximately 510kDa, harbors predominantly positive charges and is hydrophobic in nature. The holoenzyme possesses two subunits, a smaller one of 40 kDa and a larger one of 45 kDa. A third polypeptide has been found to contribute to the overall enzymatic activity, having an approximate mass of 55 kDa. The ATCase purification included the generation of cell-free extract, streptomycin sulfate cut, 60 °C heat step, ammonium sulfate cut, dialysis an

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30

Liu, Haiyan 1966. "Attenuation of Escherichia Coli Aspartate Transcarbamoylase Expressed in Pseudomonas Aeruginosa Mutant and Wild Type Strains." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc279106/.

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No apparent repression of pyr gene expression in Pseudomonas aeruginosa is observed upon addition of exogenous pyrimidines to the growth medium. Upon introduction of the subcloned Escherichia coli pyrBI genes for aspartate transcarbamoylase (ATCase) into a P. aeruginosa pyrB mutant strain, repression was observed in response to exogenously fed pyrimidine compounds. The results proved that it is possible to bring about changes in pyrimidine nucleotide pool levels and changes in transcriptional regulation of gene expression as a result. Thus, the lack of regulatory control in P. aeruginosa pyr g

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31

Boussiengui-Boussiengui, Gino. "Analysis of the role of relative nucleotide concentrations on the regulation of carbohydrate in higher plants." Thesis, Stellenbosch : Stellenbosch University, 2010. http://hdl.handle.net/10019.1/5473.

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Thesis (PhD (Genetics))--Stellenbosch University, 2010.<br>ENGLISH ABSTRACT: The current understanding of the regulation of carbohydrate accumulation is still under investigation despite the tremendous work done in this subject. Purine and pyrimidine nucleotides have been implicated in many biochemical processes in plants. Amongst others, they are building blocks for nucleic acid synthesis, an energy source, precursors for the synthesis of primary products such as sucrose, polysaccharides, phospholipids, as well as secondary products. With the aim of placing adenine and uridine nucleotides in

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32

Simpson, Luci N. "Cassette Systems for Creating Intergeneric Hybrid ATCases." Thesis, University of North Texas, 1999. https://digital.library.unt.edu/ark:/67531/metadc2237/.

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Cassette systems for creating intergeneric hybrid ATCases were constructed. An MluI restriction enzyme site was introduced at the carbamoylphosphate binding site within the pyrB genes of both Pseudomonas putida and Escherichia coli. Two hybrids, E. coli pyrB polar domain fused with P. putida pyrB equatorial domain and P. putida pyrB polar domain fused with E. coli pyrB equatorial domain, are possible. The intergeneric E. coli-P. putida hybrid pyrB gene was constructed and found to encode an active ATCase which complemented an E. coli Pyr- strain. These hybrids are useful for kinetic and expr

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33

Shen, Weiping. "Regulation of Escherichia coli pyrBI Gene Expression in Pseudomonas fluorescens." Thesis, University of North Texas, 1995. https://digital.library.unt.edu/ark:/67531/metadc278188/.

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Pseudomonas fluorescens does not appear to regulate the enzymes of de novo pyrimidine biosynthesis at the level of gene expression. Little or no apparent repression of pyr gene expression is observed upon addition of exogenous pyrimidines to the growth medium. The Escherichia coli pyrBI genes for aspartate transcarbamoylase (ATCase) were sized down and cloned into the broad host range plasmid, pKT230. Upon introduction into a P.fluorescenspyrB mutant strain, ATCase showed repression in response to exogenously fed pyrimidine compounds. Thus, it was possible to bring about changes in pyrimidine

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34

Bean, Heather D. "Prebiotic synthesis of nucleic acids." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28259.

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Thesis (M. S.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2008.<br>Committee Chair: Hud, Nicholas V.; Committee Member: Fox, Ronald F.; Committee Member: Lynn, David G.; Committee Member: Powers, James C.; Committee Member: Wartell, Roger M.; Committee Member: Williams, Loren D.

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35

Barbosa, Sara Isabel Cadinha. "Compostos que interferem no metabolismo dos purina- e pirimidina-nucleótidos: utilização como agentes terapêuticos." Master's thesis, [s.n.], 2015. http://hdl.handle.net/10284/5160.

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Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas<br>O conteúdo deste trabalho será desenvolvido em dois temas principais, um referente à utilização de compostos que interferem no metabolismo dos purina- e pirimidinanucleótidos como agentes antineoplásicos e outro referente à sua utilização como agentes antivirais. A síntese dos nucleótidos envolve a construção de ácidos nucleicos e a inserção dos derivados de nucleótidos noutras vias bioquímicas, sendo responsável por inúmera

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36

Azad, Kamran Nikkhah. "Pyrimidine Enzyme Specific Activity at Four Different Phases of Growth in Minimal and Rich Media, and Concomitant Virulence Factors Evaluation in Pseudomonas aeruginosa." Thesis, University of North Texas, 2005. https://digital.library.unt.edu/ark:/67531/metadc4918/.

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Pseudomonas aeruginosa is a Gram-negative rod, aerobic, non-fermenting, oxidase positive, pigment producing, and nutritionally versatile bacterium. Infections by P. aeruginosa are the most important cause of morbidity and mortality in immunocompromised patients, given virulence factor production that suppresses antibiotic therapy and promotes persistent infection. This research is the first comprehensive report of the pyrimidine biosynthetic pathway for all phases of growth in minimal and rich media coupled with the evaluation of virulence factor production of P. aeruginosa in comparison to

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37

Rayala, Ramanjaneyulu. "Design and Synthesis of Novel Nucleoside Analogues: Oxidative and Reductive Approaches toward Synthesis of 2'-Fluoro Pyrimidine Nucleosides." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2172.

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Fluorinated nucleosides, especially the analogues with fluorine atom(s) in the ribose ring, have been known to exert potent biological activities. The first part of this dissertation was aimed at developing oxidative desulfurization-fluorination and reductive desulfonylation-fluorination methodologies toward the synthesis of 2'-mono and/or 2',2'-difluoro pyrimidine nucleosides from the corresponding 2'-arylthiopyrimidine precursors. Novel oxidative desulfurization-difluorination methodology was developed for the synthesis of α,α-difluorinted esters from the corresponding α-arylthio esters, whe

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38

Entezampour, Mohammad. "Quantitation of Endogenous Nucleotide Pools in Pseudomonas aeruginosa." Thesis, University of North Texas, 1988. https://digital.library.unt.edu/ark:/67531/metadc500491/.

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Nucleotide pools were extracted and quantified from Pyr^+ and Pyr^- strains of P. aerucjinosa. Strains were grown in succinate minimal medium with and without pyrimidines, and nucleotides were extracted using trichloracetic acid (TCA; 6% w/v). The pyrimidine requirement was satisfied by uracil, uridine, cytosine or cytidine. Pyr^- mutants were starved for pyrimidines for two hours before nucleotide levels were measured. This starvation depleted the nucleotide pools which were restored to wild type levels by the addition of pyrimidines to the medium. When the pyrimidine analogue, 6-azauracil, k

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Visser, Daniel Finsch. "Isolation and evolution of novel nucleoside phosphorylases." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1004031.

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Approximately 33.4 million people are living with HIV/AIDS. Of those, 97% live in low and middle income countries, with 22.4 million in sub-Saharan Africa. Only 42% of the people who require anti-retrovirals (ARVs) in low to middle income countries are receiving anti-retroviral therapy (ART). There is a need to develop novel and cost effective methods for producing antiretroviral drugs. Stavudine and azidothymidine (AZT) were identified as potential targets because they could both be produced through a common intermediate – 5 methyluridine (5-MU). It has been established that the biocatalytic

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Guo, Wenyue. "A study of structure and function of two enzymes in pyrimidine biosynthesis." Thesis, Boston College, 2012. http://hdl.handle.net/2345/2772.

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Thesis advisor: Evan R. Kantrowitz<br>Nucleotides, the building blocks for nucleic acids, are essential for cell growth and replication. In E. coli the enzyme responsible for the regulation of pyrimidine nucleotide biosynthesis is aspartate transcarbamoylase (ATCase), which catalyzes the committed step in this pathway. ATCase is allosterically inhibited by CTP and UTP in the presence of CTP, the end products of the pyrimidine pathway. ATP, the end product of the purine biosynthetic pathway, acts as an allosteric activator. ATCase undergoes the allosteric transition from the low-activity and lo

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Harris, Katharine Morse. "Studies of structure, function and mechanism in pyrimidine nucleotide biosynthesis." Thesis, Boston College, 2012. http://hdl.handle.net/2345/2594.

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Thesis advisor: Evan R. Kantrowitz<br>Thesis advisor: Mary F. Roberts<br>Living organisms depend on enzymes for the synthesis using small molecule precursors of cellular building blocks. For example, the amino acid aspartate is synthesized in one step by the amination of oxaloacetate, an intermediate compound produced in the citric acid cycle, exclusively by means of an aminotransferase enzyme. Therefore, function of this aminotransferase is critical to produce the amino acid. In the Kantrowitz Lab, we seek to understand the molecular rational for the function of enzymes that control rates for

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Rodriguez, Rodriguez Mauricio. "Pyrimidine nucleotide de novo biosynthesis as a model of metabolic control." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4425.

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This manuscript presents a thorough investigation and description of metabolic control dynamics in vivo and in silico using as a model de novo pyrimidine biosynthesis. Metabolic networks have been studied intensely for decades, helping develop a detailed understanding of the way cells carry out their biosynthetic and catabolic functions. Biochemical reactions have been defined, pathway structures have been proposed, networks of genetic control have been examined, and mechanisms of enzymatic activity and regulation have been elucidated. In parallel with these types of traditional biochemical an

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Zhu, Anting [Verfasser]. "Identification and characterization of pyrimidine 5'-nucleotidases in Arabidopsis thaliana / Anting Zhu." Hannover : Technische Informationsbibliothek (TIB), 2019. http://d-nb.info/1183701845/34.

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Berthod, Thomas. "Synthèse d'oligonucléotides comportant des lésions radio- et photo-induites des bases pyrimidiques." Université Joseph Fourier (Grenoble ; 1971-2015), 1996. http://www.theses.fr/1996GRE10224.

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De nombreuses modifications des bases de l'adn peuvent etre generees par divers facteurs comme les agents oxydants ou cancerigenes, les rayonnements afin d'evaluer les consequences biologiques et physico-chimiques de ces dommages, il est necessaire de posseder des modeles plus complexes de ceux-ci qui peuvent etre obtenus par leur incorporation dans des oligonucleotides par voie chimique. Ce travail est consacre a la preparation de fragments d'adn contenant des derives de la 2'-desoxyuridine. Le premier volet de ce travail a consiste a preparer un synthon phosphoramidite de la 5-formyl-2'-deso

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Cockrell, Gregory Mercer. "New Insights into Catalysis and Regulation of the Allosteric Enzyme Aspartate Transcarbamoylase." Thesis, Boston College, 2013. http://hdl.handle.net/2345/3156.

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Thesis advisor: Evan R. Kantrowitz<br>The enzyme aspartate transcarbamoylase (ATCase) is an enzyme in the pyrimidine nucleotide biosynthetic pathway. It was once an attractive target for anti-proliferation drugs but has since become a teaching model due to kinetic properties such as cooperativity and allostery exhibited by the Escherichia coli form of the enzyme. ATCase from E. coli has been extensively studied over that last 60 years and is the textbook example of allosteric enzymes. Through this past research it is understood that ATCase is allosterically inhibited by CTP, the end product of

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Romieu, Anthony. "Synthèse d'oligonucléotides modifiés comportant des lésions radio-induites des bases puriques et pyrimidiques." Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10140.

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Divers facteurs comme des agents oxydants ou cancerigenes, les rayonnement ultraviolets et ionisants, peuvent engendrer des modifications des bases de l'adn. Afin d'evaluer les consequences biologiques et physico-chimiques de ces dommages, l'obtention de courts fragments d'adn (oligonucleotides), de sequence definie (20 a 50 bases de long) et comportant une ou plusieurs modifications en des sites bien precis est primordiale. La synthese oligonucleotidique est aujourd'hui la methode de choix pour preparer de tels composes modeles. Ce travail est consacre a la preparation de fragments d'adn synt

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Santos, Barbara Helen Cortat. "Papel biológico dos dímeros de pirimidina em células humanas irradiadas com radiação UVA." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/41/41131/tde-07122010-101150/.

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A radiação ultravioleta (UV) pode ser absorvida por diferentes moléculas celulares, incluindo o DNA no qual provoca distorções estruturais. As lesões mais comuns induzidas pela radiação UV são o ciclobutano de pirimidina (CPD) e o fotoproduto (6-4)-pirimidina-pirimidona [(6-4)PPs]. Estas lesões podem ser reparadas pela fotorreativação, caracterizada por ter uma única proteína (fotoliase) que remove lesões empregando luz visível (320-500 nm) como fonte de energia. Foram identificados dois tipos de fotoliases que diferem por sua especificidade ao substrato: CPD-fotoliase e (6-4)-fotoliase. Um ou

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Cunha, Silveira Sandra. "Voies de sauvetage du pool des pyrimidines et du NAD : des alliés inattendus dans le maintien de la stabilité du génome." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLET011.

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Le syndrome de Bloom (SB) est une maladie humaine autosomique récessive rare résultant d’une mutation sur les deux copies du gène BLM, qui code pour la protéine BLM, une 3’-5’ ADN hélicase de la sous-famille recQ. Les cellules SB présentent une forte instabilité génétique et les patients atteints du SB sont prédisposés au développement de tous les types de cancers affectant la population générale. La déplétion en BLM conduit à une chute drastique de l’expression de la cytidine désaminase (CDA), une enzyme de la voie de sauvetage des pyrimidines qui catalyse la désamination hydrolytique de la c

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Girault, Isabelle. "Identification et dosage immunologique de lésions de l'ADN." Grenoble 1, 1995. http://www.theses.fr/1995GRE10123.

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Divers facteurs (agents oxydants, rayonnements) peuvent engendrer des modifications de bases de l'adn. Le premier volet de ce travail de these a consiste a identifier les produits de degradation des bases pyrimidiques par l'ozone. L'identification de ces composes a permis de mettre en evidence deux nouveaux derives et de conclure a un mecanisme d'action specifique. La suite du travail concerne la preparation d'anticorps diriges contre des modifications de bases de l'adn. Nous avons mis au point une nouvelle methode de preparation des antigenes destines a la production d'anticorps utilises pour

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Saïag, Bernard. "Modulation de l'etat contractile du muscle lisse vasculaire par les purines, les pyrimidines et leurs recepteurs." Rennes 1, 1989. http://www.theses.fr/1989REN1A052.

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Etude de la modulation de l'etat contractile des muscles lisses arteriels (arteres caudale et femorale du rat) et veineux (veines saphene et maxillaire interne du chien) par des molecules de nature purique (adenosine. . . Atp) ou pyrimidique (utp)

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