scholarly journals Enzymatic synthesis and characterization of novel terpolymers from renewable sources

2019 ◽  
Vol 91 (3) ◽  
pp. 397-408
Author(s):  
Diana Aparaschivei ◽  
Anamaria Todea ◽  
August E. Frissen ◽  
Valentin Badea ◽  
Gerlinde Rusu ◽  
...  
Keyword(s):  
Polymerization Reaction ◽  
Molar Ratio ◽  
Condensation Polymerization ◽  
Average Molecular Mass ◽  
New Class ◽  
Platform Chemicals ◽  
Starting Point ◽  
Reaction Cycles ◽  
Methylene Group

Abstract 2,5-Furandicarboxylic acid and itaconic acid are both important biobased platform chemicals and their terpolymer with 1,6-hexanediol (HDO) can be the starting point for a new class of reactive polyesters, with important applications. The green synthetic route developed in this study involves a biocatalytic condensation polymerization reaction of dimethyl furan-2,5-dicarboxylate (DMFDC) and dimethyl itaconate (DMI) with HDO in toluene at 80°C, using commercial immobilized lipases from Candida antarctica B. In the best conditions, the formed polymer product was isolated with more than 80% yield, containing about 85% terpolymer with average molecular mass of about 1200 (Mn, calculated from MALDI-TOF MS data) and 15% DMFDC_HDO copolymer. Considering the higher reactivity of DMFDC, the composition of the synthesized polymer can be directed by adjusting the molar ratio of DMFDC and DMI, as well as by extending the reaction time. Structural analysis by NMR demonstrated the regioselective preference for the carbonyl group from DMI adjacent to the methylene group. The biocatalyst was successfully reused in multiple reaction cycles.

scholarly journals Synthesis and Characterization of Molecular Imprinting Polymer Microspheres of Cinnamic Acid: Extraction of Cinnamic Acid from Spiked Blood Plasma

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Alvin Leong Joke Chow ◽  
Showkat Ahmad Bhawani
Keyword(s):  
Cinnamic Acid ◽  
Molecular Imprinting ◽  
Binding Capacity ◽  
Polymerization Reaction ◽  
Molar Ratio ◽  
Polymer Microspheres ◽  
Acid Extraction ◽  
Imprinted Polymer ◽  
Spiked Plasma

The molecular imprinting technique is used to create the molecularly imprinted polymers (MIPs) with higher binding capacity towards the template. In this research precipitation polymerization method with noncovalent approach was used to synthesize imprinted polymer microspheres. The polymerization reaction was conducted in a flask containing acetonitrile as a porogen, cinnamic acid as a template (T), acrylic acid (AA) as a monomer, divinylbenzene (DVB) as a cross-linker, and azobisisobutyronitrile as an initiator. The polymer particles were characterized by using SEM and FTIR. The rebinding efficiency was conducted by batch binding assay and the results were monitored by using HPLC. The batch binding results suggested MIP1 (T : AA : DVB, 1 : 6 : 20 molar ratio) is most suitable composition for the rebinding of cinnamic acid. The highly selective polymer (MIP1) was used for the extraction of cinnamic acid from human plasma. The extraction efficiency of imprinted polymer of cinnamic acid from spiked plasma was above 75%.

Synthesis and characterization of poly(phthalazinone ether ketone ketone) copolymers with 4,4′-dihydroxybiphenyls

2020 ◽  
pp. 095400832095804
Author(s):  
Dalin Dong ◽  
Yuezhen Bin ◽  
Xigao Jian
Keyword(s):  
Intrinsic Viscosity ◽  
Molar Ratio ◽  
Elongation Ratio ◽  
Average Molecular Mass ◽  
Good Solubility ◽  
Comprehensive Properties ◽  
Molecular Masses ◽  
Ether Ketone ◽  
Average Molecular Masses

Meta-poly(phthalazinone ether ketone ketone) copolymers with 4,4′-dihydroxybiphenyls (meta-PPBEKK) was synthesized with 4,4′-dihydroxybiphenyls (BP), 1,3-bis(4-fluorobenzoyl)benzene (meta-DFKK) and 4-(4-hydroxyphenyl)-2,3-diazaphthalene-1-one (DHPZ). The copolymers are high-temperature resistant and have good solubility in many solvents. With increasing molar ratio of BP to meta-DFKK from 0 to 0.2, the addition of BP improves number-average molecular masses, intrinsic viscosity, mechanical properties and fluidity of meta-PPBEKKs. When the molar ratio of BP to meta-DFKK is 0.2, the intrinsic viscosity reaches 1.14 dL g−1, the number-average molecular mass reaches 44700 g mol−1, the maximum thermal elongation ratio reaches 14 with strength of 127.1 MPa and Young’s modulus of 2.4 GPa. With increasing molar ratio of BP to meta-DFKK from 0 to 0.2, meta-PPBEKKs have improved comprehensive properties, and make sense in many fields.

scholarly journals Characterization of Imidazo[4,5-d]Pyridazine Nucleosides as Modulators of Unwinding Reaction Mediated by West Nile Virus Nucleoside Triphosphatase/Helicase: Evidence for Activity on the Level of Substrate and/or Enzyme

2002 ◽  
Vol 46 (5) ◽  
pp. 1231-1239 ◽  
Author(s):  
Peter Borowski ◽  
Melanie Lang ◽  
Annemarie Haag ◽  
Herbert Schmitz ◽  
Joonho Choe ◽  
...  
Keyword(s):  
Direct Interaction ◽  
Nucleoside Analogues ◽  
Helicase Activity ◽  
West Nile ◽  
New Class ◽  
Double Stranded Dna ◽  
Starting Point ◽  
Dna Substrate ◽  
Nucleoside Triphosphatase

ABSTRACT Compounds that interact with DNA or RNA generally act as inhibitors of enzymes that unwind DNA or RNA. In the present study we describe the synthesis and properties of some nucleoside analogues that interact with double-stranded DNA but that, in contrast, facilitate the unwinding reaction mediated by West Nile (WN) virus nucleoside triphosphatase (NTPase)/helicase. The nucleoside analogues described, 1-(2′-O-methyl-β-d-ribofuranosyl)imidazo[4,5-d]pyridazine-4,7(5H,6H)-dione (HMC-HO4), 1-(β-d-ribofuranosyl)imidazo[4,5-d]pyridazine-4,7(5H,6H)-dione, and 1-(2′-deoxy-α-d-ribofuranosyl)imidazo[4,5-d]pyridazine-4,7(5H,6H)dione, all contain the imidazo[4,5-d]pyridazine ring system. The extent of the enhancing effect on helicase activity was found to be dependent on the time of exposure of the DNA substrate to the compounds and their concentrations. The nucleoside analogues were nevertheless found to be capable of uncoupling the ATPase and helicase activities of the enzyme by a mechanism operating on the level of the enzyme. Thus, in the case of HMC-HO4, the direct interaction with the enzyme caused inhibition of its helicase activity, with a half-maximal inhibitory concentration of 30 μM. The similar potency of the compound against replication of WN virus in cell culture suggests that inhibition of the helicase activity of the viral enzyme is responsible for the observed antiviral activity of HMC-HO4 and may indeed represent an important mode of action of antiviral drugs in general. Comparative studies performed with the related NTPase/helicase from hepatitis C virus revealed that the extent of the effects mediated by imidazo[4,5-d]pyridazine nucleosides is enzyme specific. The substances described may represent a starting point for the development of a new class of helicase-specific antivirals.

Targeting IDH Mutations in AML: Wielding the Double-edged Sword of Differentiation

2020 ◽  
Vol 20 (7) ◽  
pp. 490-500 ◽  
Author(s):  
Justin S. Becker ◽  
Amir T. Fathi
Keyword(s):  
Genome Structure ◽  
Cellular Metabolism ◽  
Standard Of Care ◽  
Competitive Inhibitor ◽  
Driver Mutations ◽  
New Class ◽  
Regulatory Enzymes ◽  
Idh Mutations ◽  
Genomic Characterization

The genomic characterization of acute myeloid leukemia (AML) by DNA sequencing has illuminated subclasses of the disease, with distinct driver mutations, that might be responsive to targeted therapies. Approximately 15-23% of AML genomes harbor mutations in one of two isoforms of isocitrate dehydrogenase (IDH1 or IDH2). These enzymes are constitutive mediators of basic cellular metabolism, but their mutated forms in cancer synthesize an abnormal metabolite, 2- hydroxyglutarate, that in turn acts as a competitive inhibitor of multiple gene regulatory enzymes. As a result, leukemic IDH mutations cause changes in genome structure and gene activity, culminating in an arrest of normal myeloid differentiation. These discoveries have motivated the development of a new class of selective small molecules with the ability to inhibit the mutant IDH enzymes while sparing normal cellular metabolism. These agents have shown promising anti-leukemic activity in animal models and early clinical trials, and are now entering Phase 3 study. This review will focus on the growing preclinical and clinical data evaluating IDH inhibitors for the treatment of IDH-mutated AML. These data suggest that inducing cellular differentiation is central to the mechanism of clinical efficacy for IDH inhibitors, while also mediating toxicity for patients who experience IDH Differentiation Syndrome. Ongoing trials are studying the efficacy of IDH inhibitors in combination with other AML therapies, both to evaluate potential synergistic combinations as well as to identify the appropriate place for IDH inhibitors within existing standard-of-care regimens.

scholarly journals Identification of 3,4-Dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine Derivatives as Novel Selective Inhibitors of Plasmodium falciparum Dihydroorotate Dehydrogenase

2021 ◽  
Vol 22 (13) ◽  
pp. 7236
Author(s):  
Endah Dwi Hartuti ◽  
Takaya Sakura ◽  
Mohammed S. O. Tagod ◽  
Eri Yoshida ◽  
Xinying Wang ◽  
...  
Keyword(s):  
Drug Target ◽  
De Novo ◽  
Dihydroorotate Dehydrogenase ◽  
Chemical Library ◽  
New Class ◽  
De Novo Biosynthesis ◽  
Starting Point ◽  
Novel Drugs ◽  
Low Toxicity ◽  
Fourth Step

Plasmodium falciparum’s resistance to available antimalarial drugs highlights the need for the development of novel drugs. Pyrimidine de novo biosynthesis is a validated drug target for the prevention and treatment of malaria infection. P. falciparum dihydroorotate dehydrogenase (PfDHODH) catalyzes the oxidation of dihydroorotate to orotate and utilize ubiquinone as an electron acceptor in the fourth step of pyrimidine de novo biosynthesis. PfDHODH is targeted by the inhibitor DSM265, which binds to a hydrophobic pocket located at the N-terminus where ubiquinone binds, which is known to be structurally divergent from the mammalian orthologue. In this study, we screened 40,400 compounds from the Kyoto University chemical library against recombinant PfDHODH. These studies led to the identification of 3,4-dihydro-2H,6H-pyrimido[1,2-c][1,3]benzothiazin-6-imine and its derivatives as a new class of PfDHODH inhibitor. Moreover, the hit compounds identified in this study are selective for PfDHODH without inhibition of the human enzymes. Finally, this new scaffold of PfDHODH inhibitors showed growth inhibition activity against P. falciparum 3D7 with low toxicity to three human cell lines, providing a new starting point for antimalarial drug development.

scholarly journals Synthesis and Characterization of Partially Renewable Oleic Acid-Based Ionomers for Proton Exchange Membranes

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 130
Author(s):  
Carlos Corona-García ◽  
Alejandro Onchi ◽  
Arlette A. Santiago ◽  
Araceli Martínez ◽  
Daniella Esperanza Pacheco-Catalán ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Proton Conductivity ◽  
Electrochemical Impedance ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Molar Ratio ◽  
Aromatic Diamines ◽  
Chemical Structures ◽  
Long Chain

The future availability of synthetic polymers is compromised due to the continuous depletion of fossil reserves; thus, the quest for sustainable and eco-friendly specialty polymers is of the utmost importance to ensure our lifestyle. In this regard, this study reports on the use of oleic acid as a renewable source to develop new ionomers intended for proton exchange membranes. Firstly, the cross-metathesis of oleic acid was conducted to yield a renewable and unsaturated long-chain aliphatic dicarboxylic acid, which was further subjected to polycondensation reactions with two aromatic diamines, 4,4′-(hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline and 4,4′-diamino-2,2′-stilbenedisulfonic acid, as comonomers for the synthesis of a series of partially renewable aromatic-aliphatic polyamides with an increasing degree of sulfonation (DS). The polymer chemical structures were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H, 13C, and 19F NMR) spectroscopy, which revealed that the DS was effectively tailored by adjusting the feed molar ratio of the diamines. Next, we performed a study involving the ion exchange capacity, the water uptake, and the proton conductivity in membranes prepared from these partially renewable long-chain polyamides, along with a thorough characterization of the thermomechanical and physical properties. The highest value of the proton conductivity determined by electrochemical impedance spectroscopy (EIS) was found to be 1.55 mS cm−1 at 30 °C after activation of the polymer membrane.

scholarly journals Mass Spectrometry-Based Proteomic Characterization of Cutaneous Melanoma Ectosomes Reveals the Presence of Cancer-Related Molecules

2020 ◽  
Vol 21 (8) ◽  
pp. 2934 ◽  
Author(s):  
Magdalena Surman ◽  
Sylwia Kędracka-Krok ◽  
Dorota Hoja-Łukowicz ◽  
Urszula Jankowska ◽  
Anna Drożdż ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Protein Content ◽  
Cell Lines ◽  
Cutaneous Melanoma ◽  
Epithelial Mesenchymal Transition ◽  
Mesenchymal Transition ◽  
Starting Point ◽  
Novel Biomarkers

Cutaneous melanoma (CM) is an aggressive type of skin cancer for which effective biomarkers are still needed. Recently, the protein content of extracellular vesicles (ectosomes and exosomes) became increasingly investigated in terms of its functional role in CM and as a source of novel biomarkers; however, the data concerning the proteome of CM-derived ectosomes is very limited. We used the shotgun nanoLC–MS/MS approach to the profile protein content of ectosomes from primary (WM115, WM793) and metastatic (WM266-4, WM1205Lu) CM cell lines. Additionally, the effect exerted by CM ectosomes on recipient cells was assessed in terms of cell proliferation (Alamar Blue assay) and migratory properties (wound healing assay). All cell lines secreted heterogeneous populations of ectosomes enriched in the common set of proteins. A total of 1507 unique proteins were identified, with many of them involved in cancer cell proliferation, migration, escape from apoptosis, epithelial–mesenchymal transition and angiogenesis. Isolated ectosomes increased proliferation and motility of recipient cells, likely due to the ectosomal transfer of different cancer-promoting molecules. Taken together, these results confirm the significant role of ectosomes in several biological processes leading to CM development and progression, and might be used as a starting point for further studies exploring their diagnostic and prognostic potential.

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