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Enzyme degradable polymers

Yuan Ou, Kai Chen, Hao Cai, Hu Zhang, Qiyong Gong, Jian Wang, Wei Chen, Kui Luo
In this study, to enhance the therapeutic function and reduce the side-effects of doxorubicin (DOX), a biodegradable N-(2-hydroxypropyl) methacrylamide (HPMA) polymer-DOX conjugate has been prepared through reversible addition fragmentation chain transfer (RAFT) polymerization and conjugation chemistry, and the anticancer agent DOX was covalently linked to the polymeric vehicle through a pH-responsive hydrazone bond. The cellular mechanisms of the conjugate were explored, and the therapeutic indexes were studied as well...
March 22, 2018: Biomaterials Science
Nathaniel E Kallmyer, Joseph Musielwicz, Joel Sutter, Nigel Forest Reuel
Hydrolytic enzymes are a topic of continual study and improvement due to their industrial impact and biological implications; however, the ability to measure the activity of these enzymes, especially in high-throughput assays, is limited to an established, few enzymes and often involves the measurement of secondary byproducts or the design of a complex degradation probe. Herein, a versatile single-walled carbon nanotube (SWNT)-based biosensor that is straightforward to produce and measure is described. The hydrolytic enzyme substrate is rendered as an amphiphilic polymer which is then used to solubilize the hydrophobic nanotubes...
March 20, 2018: Analytical Chemistry
Aritri Sanyal, Runa Antony, Gautami Samui, Meloth Thamban
Cryoconite holes (cylindrical melt-holes on the glacier surface) are important hydrological and biological systems within glacial environments that support diverse microbial communities and biogeochemical processes. This study describes retrievable heterotrophic microbes in cryoconite hole water from three geographically distinct sites in Antarctica, and a Himalayan glacier, along with their potential to degrade organic compounds found in these environments. Microcosm experiments (22 days) show that 13-60% of the dissolved organic carbon in the water within cryoconite holes is bio-available to resident microbes...
March 2018: Microbiological Research
Reenu Anne Joy, Narendranath Vikkath, Prasanth S Ariyannur
Hyaluronan is a ubiquitous high-molecular weight polymer of repeated disaccharides of glucuronic acid and N-acetylglucosamine. It is a membrane-bound, viscous material extruded into the extracellular matrix after being synthesized in the cytoplasm by hyaluronan synthases complex and a regulated degradation by a group of enzymes called hyaluronidases. Hyaluronan has varied biological roles on many vital organismal functions, such as cellular and tissue development, migration and repair after injury or inflammation and cancer genesis...
March 28, 2018: Drug Metabolism and Personalized Therapy
Peng Chen, Yueming Zhu, Yan Men, Yan Zeng, Yuanxia Sun
Alginate oligosaccharides with different bioactivities can be prepared through the specific degradation of alginate by alginate lyases. Therefore, alginate lyases that can be used to degrade alginate under mild conditions have recently attracted public attention. Although various types of alginate lyases have been discovered and characterized, few can be used in industrial production. In this study, AlgA, a novel alginate lyase with high specific activity, was purified from the marine bacterium Bacillus sp...
March 9, 2018: Marine Drugs
Susanne Herbst, Martin Lorkowski, Olga Sarenko, Thi Kim Loan Nguyen, Tina Jaenicke, Regine Hengge
The nucleotide second messenger c-di-GMP nearly ubiquitously promotes bacterial biofilm formation, with enzymes that synthesize and degrade c-di-GMP being controlled by diverse N-terminal sensor domains. Here, we describe a novel class of widely occurring c-di-GMP phosphodiesterases (PDE) that feature a periplasmic "CSS domain" with two highly conserved cysteines that is flanked by two transmembrane regions (TM1 and TM2) and followed by a cytoplasmic EAL domain with PDE activity. Using PdeC, one of the five CSS domain PDEs of Escherichia coli K-12 , we show that DsbA/DsbB-promoted disulfide bond formation in the CSS domain reduces PDE activity...
March 7, 2018: EMBO Journal
Mengqun Yao, Yinchu Ma, Hang Liu, Malik Ihsanullah Khan, Song Shen, Shuya Li, Yangyang Zhao, Yi Liu, Guoqing Zhang, Xiaoqiu Li, Fei Zhong, Wei Jiang, Yucai Wang
Multidrug resistance (MDR) is the major cause for chemotherapy failure, which constitutes a formidable challenge in the field of cancer therapy. The synergistic chemo-photothermal treatment has been reported to be a potential strategy to overcome MDR. In this work, rationally designed enzyme-degradable, hyperbranched polyphosphoester nanomedicines were developed for reversing MDR via the co-delivery of doxorubicin and IR-780 (hPPEDOX&IR) as combined chemo-photothermal therapy. The amphiphilic hyperbranched polyphosphoesters with phosphate bond as the branching point were synthesized via a simple but robust one-step polycondensation reaction...
March 7, 2018: Biomacromolecules
Pornpimol Phuengmaung, Daisuke Fujiwara, Wasana Sukhumsirichart, Tatsuji Sakamoto
In previous reports, we characterized four endo-xylanases produced by Streptomyces sp. strain SWU10 that degrade xylans to several xylooligosaccharides. To obtain a set of enzymes to achieve complete xylan degradation, a β-d-xylosidase gene was cloned and expressed in Escherichia coli, and the recombinant protein, named rSWU43A, was characterized. SWU43A is composed of 522 amino acids and does not contain a signal peptide, indicating that the enzyme is an intracellular protein. SWU43A was revealed to contain a Glyco_hydro_43 domain and possess the three conserved amino acid residues of the glycoside hydrolase family 43 proteins...
May 2018: Enzyme and Microbial Technology
Songkui Cui, Syogo Wada, Yuki Tobimatsu, Yuri Takeda, Simon B Saucet, Toshiyuki Takano, Toshiaki Umezawa, Ken Shirasu, Satoko Yoshida
Parasitic plants in the family Orobanchaceae are destructive weeds of agriculture worldwide. The haustorium, an essential parasitic organ used by these plants to penetrate host tissues, is induced by host-derived phenolic compounds called haustorium-inducing factors (HIFs). The origin of HIFs remains unknown, although the structures of lignin monomers resemble that of HIFs. Lignin is a natural phenylpropanoid polymer, commonly found in secondary cell walls of vascular plants. We therefore investigated the possibility that HIFs are derived from host lignin...
March 2, 2018: New Phytologist
Chunyu Zhang, Xiaoyan Dong, Zheng Guo, Yan Sun
Enzymes are promising biocatalysts for the production or degradation of chemical compounds, but low stabilities of free enzymes restrict their industrial applications. Therefore, development of effective immobilization methods to maintain or increase enzyme activity and stability remains a challenge. In this work, a novel support made of zwitterionic polymer-grafted silica nanoparticles (p-SNPs) was fabricated and Candida rugosa lipase (CRL) was covalently attached onto the p-SNPs. The zwitterionic polymer was a product of the reaction between poly(maleic anhydride-alt-1-octadecene) and N,N-dimethylenediamine and contained a cetane side chain...
February 14, 2018: Journal of Colloid and Interface Science
A E Naas, L M Solden, A D Norbeck, H Brewer, L H Hagen, I M Heggenes, A C McHardy, R I Mackie, L Paša-Tolić, M Ø Arntzen, V G H Eijsink, N M Koropatkin, M Hess, K C Wrighton, P B Pope
BACKGROUND: In nature, obligate herbivorous ruminants have a close symbiotic relationship with their gastrointestinal microbiome, which proficiently deconstructs plant biomass. Despite decades of research, lignocellulose degradation in the rumen has thus far been attributed to a limited number of culturable microorganisms. Here, we combine meta-omics and enzymology to identify and describe a novel Bacteroidetes family ("Candidatus MH11") composed entirely of uncultivated strains that are predominant in ruminants and only distantly related to previously characterized taxa...
March 1, 2018: Microbiome
Iris Fornefett, Christoph Buttersack
Inulin is a β(1 → 2) linked linear fructose polymer, the reducing end of which is capped by a glucose residue. Upon dissolution in aqueous HCl the polymer is statistically split. During the reaction progress the ratio of glucose to fructose increases and the concentration of sucrose, as an intermediate product, goes through a maximum. However, when the splitting is performed on a dealuminated faujasite zeolite, the ratio of glucose to fructose is constant and equal to the average degree of polymerization; sucrose does not appear as intermediate product...
May 1, 2018: Carbohydrate Polymers
Sung Hwa Hong, Twinkal Patel, Shell Ip, Shyam Garg, Jung Kwon Oh
Controlling the size and narrow size distribution of polymer-based nanocarriers for targeted drug delivery is an important parameter that significantly influences their colloidal stability, biodistribution, and targeting ability. Herein, we report a high-throughput microfluidic process to fabricate colloidally-stable aqueous nanoparticulate colloids with tunable sizes at 50-150 nm and narrow size distribution. The nanoparticulates are designed with different molecular weight polyesters having both ester bonds (responsive to esterase enzyme) and sulfide linkages (to oxidative reaction) on the backbones, thus exhibiting dual enzyme/oxidation responses, causing the destabilization of the nanoparticulates to lead to the controlled release of encapsulated therapeutics...
February 27, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Elite Possik, Arnim Pause
Glycogen is a main carbohydrate energy storage primarily found in fungi and animals. It is a glucose polymer that comprises α(1-4) glycosidic linkages attaching UDP-glucose molecules linearly and α(1-6) linkages branching glucose chains every 8-10 molecules to the main backbone chain. Glycogen synthase, branching enzyme, and glycogen phosphorylase are key enzymes involved in glycogen synthesis and degradation. These enzymes are tightly regulated by upstream kinases and phosphatases that respond to hormonal cues in order to coordinate storage and degradation and meet the cellular and organismal metabolic needs...
2018: Methods in Molecular Biology
Libertad Adaya, Modesto Millán, Carlos Peña, Dieter Jendrossek, Guadalupe Espín, Raunel Tinoco-Valencia, Josefina Guzmán, Daniel Pfeiffer, Daniel Segura
A novel poly-3-hydroxybutyrate depolymerase was identified in Azotobacter vinelandii. This enzyme, now designated PhbZ1, is associated to the poly-3-hydroxybutyrate (PHB) granules and when expressed in Escherichia coli, it showed in vitro PHB depolymerizing activity on native or artificial PHB granules, but not on crystalline PHB. Native PHB (nPHB) granules isolated from a PhbZ1 mutant had a diminished endogenous in vitro hydrolysis of the polyester, when compared to the granules of the wild-type strain. This in vitro degradation was also tested in the presence of free coenzyme A...
March 2018: Applied Microbiology and Biotechnology
Duoduo Wang, Trevor H Yeats, Selman Uluisik, Jocelyn K C Rose, Graham B Seymour
Fruit softening, which is a major determinant of shelf life and commercial value, is the consequence of multiple cellular processes, including extensive remodeling of cell wall structure. Recently, it has been shown that pectate lyase (PL), an enzyme that degrades de-esterified pectin in the primary wall, is a major contributing factor to tomato fruit softening. Studies of pectin structure, distribution, and dynamics have indicated that pectins are more tightly integrated with cellulose microfibrils than previously thought and have novel structural features, including branches of the main polymer backbone...
February 8, 2018: Trends in Plant Science
Dominik Danso, Christel Schmeisser, Jennifer Chow, Wolfgang Zimmermann, Ren Wei, Christian Leggewie, Xiangzhen Li, Terry Hazen, Wolfgang R Streit
Polyethylene terephthalate (PET) is one of the most important synthetic polymers used nowadays. Unfortunately, the polymers accumulate in nature and until now, no highly active enzymes are known that can degrade it at high velocity. Enzymes involved in PET degradation are mainly α/β-hydrolases like cutinases and related enzymes (E.C. 3.1.-). Currently, only a small number of such enzymes are well characterized. Within this work, a search algorithm was developed that identified 504 possible PET hydrolase candidate genes from various databases...
February 2, 2018: Applied and Environmental Microbiology
Alejandro Nieto-Orellana, David Coghlan, Malcolm Rothery, Franco H Falcone, Cynthia Bosquillon, Nick Childerhouse, Giuseppe Mantovani, Snow Stolnik
Pulmonary delivery of protein therapeutics has considerable clinical potential for treating both local and systemic diseases. However, poor protein conformational stability, immunogenicity and protein degradation by proteolytic enzymes in the lung are major challenges to overcome for the development of effective therapeutics. To address these, a family of structurally related copolymers comprising polyethylene glycol, mPEG2k, and poly(glutamic acid) with linear A-B (mPEG2k-lin-GA) and miktoarm A-B3 (mPEG2k-mik-(GA)3) macromolecular architectures was investigated as potential protein stabilisers...
February 6, 2018: International Journal of Pharmaceutics
Zhenxia Hu, Bin Deng, Xinle Tan, Hua Gan, Cheng Li, Sharif S Nada, Mitchell A Sullivan, Jialun Li, Xiaoyin Jiang, Enpeng Li, Robert G Gilbert
Glycogen is a complex branched glucose polymer functioning as a blood-sugar reservoir in animals. Liver glycogen β particles can bind together to form α particles, which have a slower enzymatic degradation to glucose. The linkage between β particles in α particles in diabetic liver breaks (is fragile) in dimethyl sulfoxide (DMSO), a H-bond disruptor, consistent with blood-sugar homeostasis loss in diabetes. We examined diurnal changes in the molecular structure of healthy and diabetic mouse-liver glycogen...
April 1, 2018: Carbohydrate Polymers
Lei Zhu, Venkata G Poosarla, Sooyeon Song, Thammajun L Wood, Daniel S Miller, Bei Yin, Thomas K Wood
Biofilms of sulfate-reducing bacteria (SRB) produce H2 S, which contributes to corrosion. Although bacterial cells in biofilms are cemented together, they often dissolve their own biofilm to allow the cells to disperse. Using Desulfovibrio vulgaris as a model SRB, we sought polysaccharide-degrading enzymes that disperse its biofilm. Using a whole-genome approach, we identified eight enzymes as putative extracellular glycoside hydrolases including DisH (DVU2239, dispersal hexosaminidase), an enzyme that we demonstrated here, by utilizing various p-nitrooligosaccharide substrates, to be an N-acetyl-β-D-hexosaminidase...
February 6, 2018: Environmental Microbiology
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