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Enzyme degradable polymers

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https://www.readbyqxmd.com/read/28436442/thermal-stability-storage-and-release-of-proteins-with-tailored-fit-in-silica
#1
Yun-Chu Chen, Tristan Smith, Robert H Hicks, Aswin Doekhie, Francoise Koumanov, Stephen A Wells, Karen J Edler, Jean van den Elsen, Geoffrey D Holman, Kevin J Marchbank, Asel Sartbaeva
Biological substances based on proteins, including vaccines, antibodies, and enzymes, typically degrade at room temperature over time due to denaturation, as proteins unfold with loss of secondary and tertiary structure. Their storage and distribution therefore relies on a "cold chain" of continuous refrigeration; this is costly and not always effective, as any break in the chain leads to rapid loss of effectiveness and potency. Efforts have been made to make vaccines thermally stable using treatments including freeze-drying (lyophilisation), biomineralisation, and encapsulation in sugar glass and organic polymers...
April 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28423064/biochemical-evaluation-of-the-anticancer-potential-of-the-polyamine-based-nanocarrier-nano11047
#2
Tracy Murray-Stewart, Elena Ferrari, Ying Xie, Fei Yu, Laurence J Marton, David Oupicky, Robert A Casero
Synthesizing polycationic polymers directly from existing drugs overcomes the drug-loading limitations often associated with pharmacologically inert nanocarriers. We recently described nanocarriers formed from a first-generation polyamine analogue, bis(ethyl)norspermine (BENSpm), that could simultaneously target polyamine metabolism while delivering therapeutic nucleic acids. In the current study, we describe the synthesis and evaluation of self-immolative nanocarriers derived from the second-generation polyamine analogue PG-11047...
2017: PloS One
https://www.readbyqxmd.com/read/28419654/degradation-and-metabolism-of-synthetic-plastics-and-associated-products-by-pseudomonas-spp-capabilities-and-challenges
#3
REVIEW
Rebecca A Wilkes, Ludmilla Aristilde
Synthetic plastics, which are widely present in materials of everyday use, are ubiquitous and slow-degrading polymers in environmental wastes. Of special interest are the capabilities of microorganisms to accelerate their degradation. Members of the metabolically-diverse genus Pseudomonas are of particular interest due their capabilities to degrade and metabolize synthetic plastics. Pseudomonas species isolated from environmental matrices have been identified to degrade polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polyethylene terephthalate, polyethylene succinate, polyethylene glycol, and polyvinyl alcohol at varying degrees of efficiency...
April 17, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28411652/strategies-for-biophysical-characterization-of-protein-polymer-conjugates
#4
Cameron Williams, Melissa L Dougherty, Katherine Makaroff, Jacob Stapleton, Dominik Konkolewicz, Jason A Berberich, Richard C Page
Protein-polymer conjugates are increasingly viewed as promising avenues to producing industrial enzymes with high activity capable of withstanding potentially harsh reaction conditions, or to designing novel therapeutics with triggered release, controlled masking, or increased resistance to proteolytic degradation. Common among these applications are the desire to improve the stability of protein-polymer conjugates to unfolding by exposure to chemicals or thermal stress. Thus, assays that allow researchers to robustly and easily characterize protein-polymer conjugates by obtaining thermodynamic parameters for folding stand to play an important role in the development of improved protein-polymer conjugates...
2017: Methods in Enzymology
https://www.readbyqxmd.com/read/28375014/mapping-the-long-range-electron-transfer-route-in-ligninolytic-peroxidases
#5
Sandra Acebes, Francisco J Ruiz-Dueñas, Mario Toubes, Veronica Sáez-Jiménez, Marta Pérez-Boada, M Fátima Lucas, Angel T Martínez, Victor Guallar
Combining a computational analysis with site-directed mutagenesis, we have studied the long-range electron transfer pathway in versatile and lignin peroxidases, two enzymes of biotechnological interest that play a key role for fungal degradation of the bulky lignin molecule in plant biomass. The in silico study established two possible electron transfer routes starting at the surface tryptophan residue previously identified as responsible for oxidation of the bulky lignin polymer. Moreover, in both enzymes, a second buried tryptophan residue appears as a top electron transfer carrier, indicating the prevalence of one pathway...
April 14, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28371373/microbial-enzymes-for-the-recycling-of-recalcitrant-petroleum-based-plastics-how-far-are-we
#6
REVIEW
Ren Wei, Wolfgang Zimmermann
Petroleum-based plastics have replaced many natural materials in their former applications. With their excellent properties, they have found widespread uses in almost every area of human life. However, the high recalcitrance of many synthetic plastics results in their long persistence in the environment, and the growing amount of plastic waste ending up in landfills and in the oceans has become a global concern. In recent years, a number of microbial enzymes capable of modifying or degrading recalcitrant synthetic polymers have been identified...
March 28, 2017: Microbial Biotechnology
https://www.readbyqxmd.com/read/28350993/convergent-strategy-for-the-synthesis-of-s-linked-oligoxylans
#7
Beatrice Bonora, Irene Boos, Mads H Clausen
Arabinoxylans (AX) are a major class of hemicellulose and an important polysaccharide component of lignocellulosic biomass. To utilize the glycan polymer effectively, it is desirable to learn more about the enzymatic hydrolysis of AXs. Well-defined glycans can help to elucidate these processes. Here, we report the efficient synthesis of a mixed O- and S-linked tetraxylan. This thio-oligosaccharide has been developed as a putative inhibitor of arabinoxylan degrading enzymes used for the saccharification of biomass...
March 21, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28329766/complex-pectin-metabolism-by-gut-bacteria-reveals-novel-catalytic-functions
#8
Didier Ndeh, Artur Rogowski, Alan Cartmell, Ana S Luis, Arnaud Baslé, Joseph Gray, Immacolata Venditto, Jonathon Briggs, Xiaoyang Zhang, Aurore Labourel, Nicolas Terrapon, Fanny Buffetto, Sergey Nepogodiev, Yao Xiao, Robert A Field, Yanping Zhu, Malcolm A O'Neill, Breeanna R Urbanowicz, William S York, Gideon J Davies, D Wade Abbott, Marie-Christine Ralet, Eric C Martens, Bernard Henrissat, Harry J Gilbert
The metabolism of carbohydrate polymers drives microbial diversity in the human gut microbiota. It is unclear, however, whether bacterial consortia or single organisms are required to depolymerize highly complex glycans. Here we show that the gut bacterium Bacteroides thetaiotaomicron uses the most structurally complex glycan known: the plant pectic polysaccharide rhamnogalacturonan-II, cleaving all but 1 of its 21 distinct glycosidic linkages. The deconstruction of rhamnogalacturonan-II side chains and backbone are coordinated to overcome steric constraints, and the degradation involves previously undiscovered enzyme families and catalytic activities...
April 6, 2017: Nature
https://www.readbyqxmd.com/read/28324320/tailoring-the-properties-of-mpeg-plla-nanoparticles-for-better-encapsulation-and-tuned-release-of-the-hydrophilic-anticancer-drug
#9
Sachin S Surwase, Neha M Munot, Bhaskar B Idage, Susheela B Idage
Gemcitabine is used as a first-line drug for treating many solid tumours. However, it suffers from a major drawback of strong side effects and short plasma half-life because of degradation by enzyme when administered intravenously. Polyesters and copolyesters are the most widely used and preferred class of biodegradable polymer. In the present work, efforts have been made to prepare poly(ethylene glycol) monomethoxy ether-poly(L-lactide) (mPEG-PLLA), a biodegradable amphiphilic copolymer with a view to improve the entrapment and tuned release of hydrophilic drug gemcitabine...
March 21, 2017: Drug Delivery and Translational Research
https://www.readbyqxmd.com/read/28319778/polyhydroxyalkanoates-pha-production-from-synthetic-waste-using-pseudomonas-pseudoflava-pha-synthase-enzyme-activity-analysis-from-p-pseudoflava-and-p-palleronii
#10
M Venkateswar Reddy, Yasuteru Mawatari, Rui Onodera, Yuki Nakamura, Yuka Yajima, Young-Cheol Chang
Synthetic wastewater (SW) at various carbon concentrations (5-60g/l) were evaluated for polyhydroxyalkanoates (PHA) production using the bacteria Pseudomonas pseudoflava. Bacteria showed highest PHA production with 20g/l (57±5%), and highest carbon removal at 5g/l (74±6%) concentrations respectively. Structure, molecular weight, and thermal properties of the produced PHA were evaluated using various analytical techniques. Bacteria produced homo-polymer [poly-3-hydroxybutyrate (P3HB)] when only acetate was used as carbon source; and it produced co-polymer [poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV)] by addition of co-substrate propionate...
March 4, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28314873/exploring-the-bioprospecting-and-biotechnological-potential-of-white-rot-and-anaerobic-neocallimastigomycota-fungi-peptidases-esterases-and-lignocellulolytic-enzymes
#11
REVIEW
Ronivaldo Rodrigues da Silva, Rafael Pedezzi, Tatiane Beltramini Souto
Fungi constitute an invaluable natural resource for scientific research, owing to their diversity; they offer a promising alternative for bioprospecting, thus contributing to biotechnological advances. For a long time, extensive information has been exploited and fungal products have been tested as a source of natural compounds. In this context, enzyme production remains a field of interest, since it offers an efficient alternative to the hazardous processes of chemical transformations. Owing to their vast biodiversity and peculiar biochemical characteristics, two fungal categories, white-rot and anaerobic Neocallimastigomycota, have gathered considerable attention for biotechnological applications...
March 17, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28285078/biodegradable-inorganic-organic-hybrids-of-methacrylate-star-polymers-for-bone-regeneration
#12
Justin J Chung, Yuki Fujita, Siwei Li, Molly M Stevens, Toshihiro Kasuga, Theoni K Georgiou, Julian R Jones
Hybrids that are molecular scale co-networks of organic and inorganic components are promising biomaterials, improving the brittleness of bioactive glass and the strength of polymers. Methacrylate polymers have high potential as the organic source for hybrids since they can be produced, through controlled polymerization, with sophisticated polymer architectures that can bond to silicate networks. Previous studies showed the mechanical properties of hybrids can be modified by polymer architecture and molar mass (MM)...
March 8, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28277671/enzyme-cleavable-polymeric-micelles-for-the-intracellular-delivery-of-proapoptotic-peptides
#13
Hanna B Kern, Selvi Srinivasan, Anthony J Convertine, David Hockenbery, Oliver W Press, Patrick S Stayton
Peptides derived from the third Bcl-2 homology domain (BH3) renormalize apoptotic signaling by antagonizing prosurvival Bcl-2 family members. These potential peptide drugs exhibit therapeutic activities but are limited by barriers including short circulation half-lives and poor penetration into cells. A diblock polymeric micelle carrier for the BIM BH3 peptide was recently described that demonstrated antitumor activity in a B-cell lymphoma xenograft model [Berguig et al., Mol. Ther. 2015, 23, 907-917]. However, the disulfide linkage used to conjugate the BIM peptide was shown to have nonoptimal blood stability...
March 30, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28270073/colon-cancer-and-specific-ways-to-deliver-drugs-to-the-large-intestine
#14
Hossein Derakhshankhah, Zhila Izadi, Alireza Lotfabadi, Loghman Alaei, Ali Akbar Saboury, Rassoul Dinarvand, Adeleh Divsalar, Arefeh Seyedarabi, Ebrahim Barzegari, Mina Evini
BACKGROUND: It has been postulated that colon cancer is the third cause of cancer death worldwide. Recently, colon-targeted drug delivery systems have been developed for improving systemic drug delivery and treatment of local colon associated diseases. Using such drug delivery systems increases the drug's effectiveness and results in reduced systemic side effects. Drug delivery systems formulated for the colon requires that the triggering of drug release mechanism is designed based on the colon's physiological conditions...
February 13, 2017: Anti-cancer Agents in Medicinal Chemistry
https://www.readbyqxmd.com/read/28267318/modular-synthetic-approach-for-adjusting-the-disassembly-rates-of-enzyme-responsive-polymeric-micelles
#15
Assaf J Harnoy, Marina Buzhor, Einat Tirosh, Rona Shaharabani, Roy Beck, Roey J Amir
Self-assembled nanostructures and their stimuli-responsive degradation have been recently explored to meet the increasing need for advanced biocompatible and biodegradable materials for various biomedical applications. Incorporation of enzymes as triggers that can stimulate the degradation and disassembly of polymeric assemblies may be highly advantageous owing to their high selectivity and natural abundance in all living organisms. One of the key factors to consider when designing enzyme-responsive polymers is the ability to fine-tune the sensitivity of the platform toward its target enzyme in order to control the disassembly rate...
March 21, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28252940/design-strategies-of-stimuli-responsive-supramolecular-hydrogels-relying-on-structural-analyses-and-cell-mimicking-approaches
#16
Hajime Shigemitsu, Itaru Hamachi
Stimuli-responsive hydrogels are intriguing biomaterials useful for spatiotemporal controlled release of drugs, cells, and biological cues, cell engineering for various applications, and medical diagnosis. To date, many physical and chemical stimuli-responsive polymer hydrogels have been developed by chemical modification of polymer chains and cross-linking points. In particular, conjugation with biomolecules to polymers produced promising biomolecule-responsive hydrogels. These examples clearly indicate high potentials of stimuli-responsive hydrogels as promising biomaterials...
March 2, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28251581/chitin-and-its-effects-on-inflammatory-and-immune-responses
#17
REVIEW
Daniel Elieh Ali Komi, Lokesh Sharma, Charles S Dela Cruz
Chitin, a potential allergy-promoting pathogen-associated molecular pattern (PAMP), is a linear polymer composed of N-acetylglucosamine residues which are linked by β-(1,4)-glycosidic bonds. Mammalians are potential hosts for chitin-containing protozoa, fungi, arthropods, and nematodes; however, mammalians themselves do not synthetize chitin and thus it is considered as a potential target for recognition by mammalian immune system. Chitin is sensed primarily in the lungs or gut where it activates a variety of innate (eosinophils, macrophages) and adaptive immune cells (IL-4/IL-13 expressing T helper type-2 lymphocytes)...
March 1, 2017: Clinical Reviews in Allergy & Immunology
https://www.readbyqxmd.com/read/28250957/the-mechanism-behind-the-selection-of-two-different-cleavage-sites-in-nag-nam-polymers
#18
Marko Mihelič, Kristina Vlahoviček-Kahlina, Miha Renko, Stephane Mesnage, Andreja Doberšek, Ajda Taler-Verčič, Andreja Jakas, Dušan Turk
Peptidoglycan is a giant molecule that forms the cell wall that surrounds bacterial cells. It is composed of alternating N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) residues connected by β-(1,4)-glycosidic bonds and cross-linked with short polypeptide chains. Owing to the increasing antibiotic resistance against drugs targeting peptidoglycan synthesis, studies of enzymes involved in the degradation of peptidoglycan, such as N-acetylglucos-aminidases, may expose new, valuable drug targets. The scientific challenge addressed here is how lysozymes, muramidases which are likely to be the most studied enzymes ever, and bacterial N-acetylglucosaminidases discriminate between two glycosidic bonds that are different in sequence yet chemically equivalent in the same NAG-NAM polymers...
March 1, 2017: IUCrJ
https://www.readbyqxmd.com/read/28242654/cellulose-derived-oligomers-act-as-damage-associated-molecular-patterns-and-trigger-defense-like-responses
#19
Clarice de Azevedo Souza, Shundai Li, Andrew Z Lin, Freddy Boutrot, Guido Grossmann, Cyril Zipfel, Shauna C Somerville
The plant cell wall, often the site of initial encounters between plants and their microbial pathogens, is composed of a complex mixture of cellulose, hemicellulose, and pectin polysaccharides as well as proteins. The concept of damage-associated molecular patterns (DAMPs) was proposed to describe plant elicitors like oligogalacturonides (OGs), which can be derived by the breakdown of the pectin homogalacturon by pectinases. OGs act via many of the same signaling steps as pathogen- or microbe-associated molecular patterns (PAMPs) to elicit defenses and provide protection against pathogens...
April 2017: Plant Physiology
https://www.readbyqxmd.com/read/28238914/biochemical-and-biophysical-properties-of-a-metagenome-derived-gh5-endoglucanase-displaying-an-unconventional-domain-architecture
#20
Agnes C Pimentel, Gabriela C G Ematsu, Marcelo V Liberato, Douglas A A Paixão, João Paulo L Franco Cairo, Fernanda Mandelli, Robson Tramontina, César A Gandin, Mario de Oliveira Neto, Fabio M Squina, Thabata M Alvarez
Endoglucanases are key enzymes in the degradation of cellulose, the most abundant polymer on Earth. The aim of this work was to perform the biochemical and biophysical characterization of CelE2, a soil metagenome derived endoglucanase. CelE2 harbors a conserved domain from glycoside hydrolase family 5 (GH5) and a C-terminal domain with identity to Calx-beta domains. The recombinant CelE2 displayed preference for hydrolysis of oat beta-glucan, followed by lichenan and carboxymethyl cellulose. Optimum values of enzymatic activity were observed at 45°C and pH 5...
June 2017: International Journal of Biological Macromolecules
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