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Propionyl holocarboxylase synthesisHuang, Shu Chin January 1963 (has links)
A soluble enzyme system, isolated from livers of biotin-deficient rats, catalyzes the ATP-dependent synthesis of propionyl holocarboxylase from d-biotin and propionyl apocarboxylase. This system has been resolved by alumina C<sub>∂</sub> gel fractionation into two essential components; (a) gel supernatant which contains propionyl apocarboxylase and (b) gel eluate which contains an enzyme which catalyzes the covalent bonding of d-biotin to propionyl apocarboxylase. The propionyl holocarboxylase synthesis catalyzed by these enzyme systems is irreversible and d·biotin specific. The gel supernatant has been further purified by hydroxyapatite chromatography and (NH₄)₂SO₄ fractionation and the gel eluate by (NH₄)₂SO₄ precipitation and cellulose-phosphate chromatography. An enzyme similar to the gel eluate enzyme has been isolated from cell-free extracts of Propionibacterium shermanii. Although cell-free extracts of P. shermanii do not contain propionyl apo- or holocarboxylase, they do catalyze ATP-dependent propionyl holocarboxylase formation from d·biotin and rat liver propionyl apocarboxylase. Biotin-2'-C¹⁴-labelled propionyl holocarboxylaae, synthesized with these enzyme systems, does not transfer C¹⁴O₂ to propionyl-CoA indicating that the ureido carbon of enzyme-bound biotin is not the"active carbon" of biotin. / Master of Science
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Maleimide-thiol linkages alter the biodistribution of SN38 therapeutic microbubbles compared to biotin-avidin while preserving parity in tumoral drug deliveryIngram, N., Abou-Saleh, R.H., Race, Amanda D., Loadman, Paul, Bushby, R.J., Evans, S.D., Coletta, P.L. 29 August 2024 (has links)
Yes / Therapeutic microbubbles (thMBs) contain drug-filled liposomes linked to microbubbles and targeted to vascular proteins. Upon the application of a destructive ultrasound trigger, drug uptake to tumour is improved. However, the structure of thMBs currently uses powerful non-covalent bonding of biotin with avidin-based proteins to link both the liposome to the microbubble (MB) and to bind the targeting antibody to the liposome-MB complex. This linkage is not currently FDA-approved, and therefore, an alternative, maleimide-thiol linkage, that is currently used in antibody-drug conjugates was examined. In a systematic manner, vascular endothelial growth factor receptor 2 (VEGFR2)-targeted MBs and thMBs using both types of linkages were examined for their ability to specifically bind to VEGFR2 in vitro and for their ultrasound imaging properties in vivo. Both showed equivalence in the production of the thMB structure, in vitro specificity of binding and safety profiles. In vivo imaging showed subtle differences for thMBs where biotin thMBs had a faster wash-in rate than thiol thMBs, but thiol thMBs were longer-lived. The drug delivery to tumours was also equivalent, but interestingly, thiol thMBs altered the biodistribution of delivery away from the lungs and towards the liver compared to biotin thMBs, which is an improvement in biosafety. / This research was funded by the EPSRC (EP/I000623/1, EP/L504993/1 and EP/P023266/1). S.D.E. is supported by the National Institute for Health Research infrastructure at Leeds.
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Impairment of gut microbial biotin metabolism and host biotin status in severe obesity: effect of biotin and prebiotic supplementation on improved metabolismBelda, Eugeni, Voland, Lise, Tremaroli, Valentina, Falony, Gwen, Adriouch, Solia, Assmann, Karen E., Prifti, Edi, Aron-Wisnewsky, Judith, Debédat, Jean, Le Roy, Tiphaine, Nielsen, Trine, Amouya, Chloé, André, Sébastien, Andreelli,, Fabrizio, Blüher, Matthias Blüher,, Chakaroun, Rima, Chilloux, Julien, Coelho, Luis Pedro, Dao, Maria Carlota, Das, Promi, Fellahi, Soraya, Forslund, Sofia, Galleron, Nathalie, Hansen, Tue, Holmes, Bridget, Ji, Boyang, Krogh Pedersen, Helle, Le, Phuong, Le Chatelier, Emmanuelle, Lewinter, Christian, Mannerås-Holm, Louise, Marquet, Florian, Myridakis, Antonis, Pelloux, Veronique, Pons, Nicolas, Quinquis, Benoit, Rouault, Christine, Roume, Hugo, Salem, Joe-Elie, Sokolovska, Nataliya, Søndertoft, Nadja B, Touch, Sothea, Vieira-Silva, Sara, Consortium, MetaCardis, Galan, Pilar, Holst, Jens, Gøtze, Jens Peter, Køber, Lars, Vestergaard, Henrik, Hansen, Torben, Hercberg, Serge, Oppert, Jean-Michel, Nielsen, Jens, Letunic, Ivica, Dumas, Marc-Emmanuel, Stumvol, Michael, Pedersen, Oluf Borbye, Bork, Peer, Dusko Ehrlich, Stanislav, Zucker, Jens-Daniel, Bäckhed, Fredrik, Raes, Jeroen, Clément, Karine 02 August 2024 (has links)
Gut microbiota is a key component in
obesity and type 2 diabetes, yet mechanisms and
metabolites central to this interaction remain unclear.
We examined the human gut microbiome’s functional
composition in healthy metabolic state and the most
severe states of obesity and type 2 diabetes within the
MetaCardis cohort. We focused on the role of B vitamins
and B7/B8 biotin for regulation of host metabolic state,
as these vitamins influence both microbial function and
host metabolism and inflammation.
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Atributos da validação do método analítico para quantificação da biotina empregando a técnica potenciométrica /Gonçalves, Gabriela Soldi. January 2010 (has links)
Orientador: José Paschoal Batistuti / Banca: Fernando Luis Fertonani / Banca: Valeria Monterio da Silva Eleutério / Resumo: O presente trabalho consiste no desenvolvimento de um método analítico para determinação de biotina, utilizando-se a potenciometria indireta. O objetivo é apresentar a validação de método analítico como um processo que estime a eficiência do método proposto na rotina do laboratório para garantia da qualidade total. É um método que envolve equipamento simples e pouco dispendioso como o potenciômetro, que possibilita medir com precisão o valor da concentração de biotina. O doseamento quantitativo de biotina baseia-se no estudo das reações oscilantes do analito perante as análises da titulação indireta utilizando potenciômetro automático. A concentração de biotina foi determinada com massa adicionada conhecida numa matriz que simula uma cápsula, contendo aerosil (1%), estearato de magnésio (1%), celulose microcristalina (20%), amido (40%) e lactose q.s.p. Os resultados mostraram um valor médio de biotina (massa adicionada de aproximadamente 25 mg) determinada de 99,4% com desvio-padrão de 0,0345. As condições experimentais como temperatura, vidraria e concentração dos reagentes foram otimizadas. Os parâmetros investigados no processo de validação para demonstrar o desempenho do método foram: especificidade, linearidade, intervalo, precisão tanto repetitividade, quanto intermediária, exatidão e robustez. O tratamento estatístico dos dados da validação do método analítico envolveu a determinação da média, do desvio padrão e do coeficiente de variação. Para obtenção da curva de calibração se fez necessária a determinação da equação da reta, regressão linear e coeficiente de correlação linear. Este método apresenta grande aplicabilidade em soluções turvas, fluorescentes, opacas ou coradas, ou quando não existem, ou não podem aplicar-se indicadores visuais apropriados. Há possibilidade de determinação... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present work shows the development of an analytical method for the determination of biotin by using indirect potentiometry. The main goal is to present the validation of analytical methods as a process to estimate the efficiency of the proposed methodology in the laboratory routine for the guaranty of total quality. This method involves simple and low cost devices as the potentiometer, which allows the precise measurement of biotin concentration. The quantitative dosing of biotin is based on the study of the oscillating chemical reactions with the analyte by performing the analysis of the indirect titration with an automatic potentiometer. Biotin concentration was determined by adding a known mass to a matrix that simulates a capsule containing aerosol (1%), estearato de magnésio (1%), celulose microcristalina (20%), amido (40%) e lactose q.s.p. The results showed an average value for the determination of biotin (added mass was ca. 25 mg) of 99.4% with a standard deviation of 0.0345. The experimental conditions as temperature, glassware, and concentration of the chemicals were optimized. The investigated parameters of the validation procedure to demonstrate the performance of the method were: specificity, linearity, interval, precision (repeatability and intermediate), exactness and robustness. The statistical treatment of the data for the validation of the analytical method involved the determination of the average value, standard deviation, and the variation coefficient. In order to obtain the calibration curve, the line's equation, the linear regression and the coefficient of linear correlation were determined. This method shows great applicability for turbid, fluorescent, opaque or color solutions, or if an appropriate visual indicator is not available or cannot be applied. The method also shows the possibility for the determination of a sequence of equivalence... (Complete abstract click electronic access below) / Mestre
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Molecular genetics of biotin-dependent enzymes : mutation analysis, expression and biochemical studiesCampeau, Eric. January 1999 (has links)
No description available.
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Biotinylation and high affinity avidin capture as a strategy for LC-MS based metabolomicsRhönnstad, Sofie January 2010 (has links)
<p>Metabolites, small endogenous molecules existing in every living cell, tissue or organism, play a vital role for maintaining life. The collective group of all metabolites, the metabolome, is a consequence of the biochemistry and biochemical pathways that a cell or tissue uses to promote survival. Analysis of the metabolome can be done to reveal changes of specific metabolites which can be a manifestation, a reason or a consequence of for example a disease. The physical chemical diversity amongst these components is tremendous and it poses a large analytical challenge to measure and quantify all of them. Targeting sub groups of the metabolome such as specific functional classes has shown potential for increasing metabolite coverage. Group selective labeling with biotin-tags followed by high affinity avidin capture is a well established purification strategy for protein purification.</p><p>The purpose with this project is to explore if it is possible to transfer the avidin biotin approach to metabolomics and use this method for small molecules purification. Specifically, this investigation aims to see if it is achievable to make a biotinylation of specific functional groups, to increase the sensitivity through reduction of sample complexity in liquid chromatography mass spectrometry metabolomics analyses after high affinity avidin capture. By purifying the analyte of interest and thereby reducing the sample complexity there will be a reduction in ion suppression. The aim is to increase the analytical sensitivity through a reduction in ion suppression during liquid chromatography mass spectrometry analysis.</p><p>Delimitations have been done to only investigate the possibility to obtain a biotinylation of primary amines and amides. As model compounds phenylalanine, spermidine, histamine and nicotinamide have been selected.</p><p>The result from this study indicates that it is possible to increase metabolite coverage through biotin labeling followed by high affinity avidin capture. It is a gain in analytical sensitivity of selected model compounds when comparing biotinylation strategy with a control nonbiotinylation approach in a complex sample. A broader study of additional model compounds and a method development of this strategy are necessary to optimize a potential future method.</p>
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Association Behavior of Biotinylated and Non-Biotinylated PolyEthylene Oxide-b-Poly(2-(Diethylamino)Ethyl Methacrylate)Tan, J. F., Ravi, P., Too, Heng-Phon, Hatton, T. Alan, Tam, K. C. 01 1900 (has links)
Biotinylated and non-biotinylated copolymers of ethylene oxide (EO) and 2-(diethylamino)ethyl methacrylate (DEAEMA) were synthesized by the atom transfer radical polymerization technique (ATRP). The chemical compositions of the copolymers as determined by NMR are represented by PEO₁₁₃PDEAEMA₇₀ and biotin-PEO₁₀₄PDEAEMA₉₃ respectively. The aggregation behavior of these polymers in aqueous solutions at different pHs and ionic strengths was studied using a combination of potentiometric titration, dynamic light scattering (DLS), static light scattering (SLS), and transmission electron microscopy (TEM). Both PEO-b-PDEAEMA and biotin-PEO-b-PDEAEMA diblock copolymers form micelles at high pH with hydrodynamic radii (Rh) of about 19 and 23 nm, respectively. At low pH, the copolymers are dispersed as unimers in solution with Rh of about 6-7 nm. However, at a physiological salt concentration (cs) of about 0.16M NaCl and a pH of 7-8, the copolymers form large loosely packed Guassian chains, which were not present at the low cs of 0.001M NaCl. The critical micelle concentrations (CMC) and the cytotoxicity of the copolymers were investigated to determine a suitable polymer concentration range for future biological applications. Both PEO-b-PDEAEMA and biotin-PEO-b-PDEAEMA diblock copolymers possess identical CMC values of about 0.0023 mg/g, while the cytotoxicity test indicated that the copolymers are not toxic up to 0.05mg/g (> 83% cell survival at this concentration). / Singapore-MIT Alliance (SMA)
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Immunochemical Studies on the family of Biotin Binding ProteinsSubramanian, N 01 1900 (has links)
Investigations detailed in this thesis constitue a part of continuing programme of research work undertaken in this laboratory on vitamin binding proteins. Avidin from the chicken egg white, streptavidin &om the bacterium Streptromyces avidin and biotin binding proteins (BBP-I and BBP-11) from chicken egg yolk constitute a family of proteins that bind the vitamin biotin with extremely high affinities. The yolk BBPs are involved in the deposition of the vitamin in the developing oocyte in chicks whereas an antimicrobial function has been attributkl to avidin.. The fact that all these proteins bind the vitamin in the same manner, unlike biotin-dependent enzymes, indicates that the structural features involved in ligand binding could be similar, if not identical in these proteins. To delineate the basis of putative structural similarity among these proteins, studies were carried out using antibodies as the immunological probes.
Avidin, a homotetremer glycoprotein, with a subunit Mr of 17,000 has been purified to homogeneity from chicken egg white using a novel procedure involving ammonium sulphate fractionation, ethanol precipitation and S-Sepharose column chromatography. Despite their lesser abundance in chicken egg yolk associated with a large amount of interfering lipids during the purification, both BBP-I (monomer and shown to be precursor for BBP-11) and BBP-I1 (tetramer) have been purified to homogeneity by employing a common method using butanol extraction to remove the lipids, DEAE-Sephacel column chromatography, biotin-AH-Sepharose affinity chromatography and fast performance liquid chrometography (FPLC) system. The purity of all these proteins was confirmed by SDS-PAGE analysis.
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Mass spectrometry-based chemical and quantitative proteomicsQiu, Haibo. January 2009 (has links)
Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Title from first page of PDF file (viewed March 8, 2010). Includes bibliographical references. Issued in print and online. Available via ProQuest Digital Dissertations.
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Untersuchungen zum ruminalen Biotinumsatz beim Rind / Studies to ruminal biotin conversion in cattleSchröder, Benjamin 15 July 2004 (has links)
No description available.
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