Chemistry Commons^™

Extracellular Expression Of Alkaline Phytase In Pichia Pastoris: Influence Of Signal Peptides, Promoters And Growth Medium, Mimi Yang, Sasha Teymorian, Philip Olivares, Pushpalatha P.N. Murthy

Michigan Tech Publications

Alkaline phytase isolated from pollen grains of Lilium longiflorum (LlALP) possesses unique catalytic and thermal stability properties that suggest it has the potential to be used as a feed supplement. However, substantial amounts of active enzymes are needed for animal feed studies and endogenous levels of LlALP in lily pollen are too low to provide the required amounts. Active rLlALP2 (coded by LlAlp2, one of two isoforms of alkaline phytase cDNA identified in lily pollen) has been successfully expressed in intracellular compartments of Pichia pastoris, however enzyme yields have been modest (25-30 mg/L) and purification of the enzyme has been …

Polymerization Of Peek Ab Monomers With Oxyalkylene Linkages Via Nas And Friedel-Crafts Reactions, Shannon Theresa Hennelly

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The synthesis of the NAS monomer, 4-fluoro-4'-(2-(4-benzyloxyphenoxy)ethoxy) benzophenone, was envisioned as a two-step process. Thus, the synthesis of 4-fluoro- 4'-(2-(4-benzyloxyphenoxy)ethoxy)benzophenone was accomplished by the reaction of 4-fluoro-4'-hydroxybenzophenone and 1-(benzyloxy)-4-(2bromoethoxy) benzene. Hydrogenation of 4-fluoro-4'-(2-(4-benzyloxyphenoxy)ethoxy) benzophenone with 10% Pd/C was used to successfully remove the benzylic ether protective group, however, the reaction also reduced the benzophenone carbonyl. The synthesis of the EAS monomer, 4-(2-(4-phenoxyphenoxy)ethoxy)benzoic acid, was also a two-step process. The reaction of ethyl p-(2-hydroxyethoxy)benzoate and 4-phenoxyphenol gave ethyl 4-(2-(4-phenoxyphenoxy)ethoxy)benzoate in good yield. This ester could be easily hydrolyzed to 4-(2-(4-pheonxyphenoxy)ethoxybenzoic acid. The polymerization of the EAS monomer, 4-(2-(4-pheonxyphenoxy)ethoxybenzoic acid, was carried …

Proxy-Pet Building Blocks As A Design Element For Library Synthesis, Lainey Jo Mallin

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In exploring radioligands for positron emission tomography (PET) imaging, it is not unusual to synthesize a library of compounds around some targeting scaffold, screen for optimal binding to a relevant diagnostic cellular target, remove some portion of optimized molecule so as to append the requisite reporter group, and then re-evaluate. To this end, the use of "click labeling" in radiochemistry is proving an increasingly attractive means of conjugating a 18F-reporter group, wherein the targeting scaffold bearing a terminal alkyne is allowed to react with a 2-[18F]-fluoroethylazide to forge a linkage as a 1,2,3-triazole substituent. Since the triazole linked prosthetic group …

Computational Estimation Of The Pka's Of Purines And Related Compounds, Kara L. Geremia

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The acid dissociation value pKa of a compound provides important information regarding the neutral and ionic forms of the compound present under different conditions. However, for many compounds experimental pKa values are not available, and for others the measured values are sometimes uncertain. Consequently, having a computational means for estimating pKa values can be of benefit for biochemical, pharmaceutical, polymer, and many other studies. Purines form a key group of bioactive compounds whose acid/base activities are of considerable interest. The purine class includes such diverse compounds as the nucleic acid bases adenine and guanine, the gout-related compound uric acid, the …

Tuning The Physical Properties Of Poly(Arylene Ether)S Prepared From 3,5-Difluorobenzene Sulfonamides, Renata Mitton

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A series of functionalized poly(arylene ether)s, PAEs, based on 3,5-difluorobenzene sulfonamides with varying groups on the sulfonamide moiety were investigated. The main goal of the project was to tune the physical properties of the PAEs by altering the organic groups present on the sulfonamide nitrogen atom, including combinations of aryl iodide, alkyl, allyl, 4-ethoxycarboxylphenyl and benzyl moieties.

Using 3,5-difluorobenzenesulfonyl chloride as a starting material, N-R1-N-R2-3,5-difluorobenzenesulfonamides were prepared, followed by conversion to the corresponding PAEs by reaction of 3,5-difluorobenzene sulfonamides with Bisphenol-A, via a typical NAS polycondensation. Copolymers with varying contents of the functional monomer ranging from 10 to 25 %, …

Work Function Modification Of Metal Electrodes Via Printing Of Pedot:Pss And Carbon Nanotubes, Carly A. Jordan

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Work function tunability of metal electrodes provides a route to improving performance of organic electronic devices. Using an electrode with a different work function changes the potential barrier at the polymer/electrode interface, leading to altered device characteristics, such as turn-on voltage in light emitting diodes or series resistance photodiodes. In this work, we explore work function modification by employing solution-based conducting materials, poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT:PSS) and carbon nanotubes (CNTs), printed as overcoatings on oxidized Ni. The capability of direct write technologies, namely inkjet and aerosol jet printing, to control thin film thickness is investigated. The correlation between film …

Investigation Of Solvent-Dependent Properties Of Donor And Acceptor Materials For Photovoltaic Applications, Anna L. Foote

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The choice of solvent and additive has been shown to affect efficiency of organic solar cell devices. To gain a basic understanding of the role of solvents in influencing overall device performance, we present a comparative study on the physical properties of donor: acceptor mixtures in different solvents. Investigations have been carried out for P3HT (poly(3-hexylthiophene-2,5-diyl)), PTB7 (poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']-dithiophene-2,6-diyl][3-fluro-2-[2-ethylhexyl)carbonyl[thieno[3,4-b]thiophenediyl]]), PC61BM ([6,6]-phenyl-C60-butyric acid methyl ester), and PC71BM ([6,6]-phenyl-C70-butyric acid methyl ester). The physical properties reported are based on UV-Vis absorption spectroscopy, resistance measurements, cyclic voltammetry measurements, and surface energy characterizations of the organic films. The solvents used to prepare the organic films …