scholarly journals Molecular basis of scavenging effect of zonisamide on hydroxyl radical <i>in vitro</i>

2012 ◽  
Vol 03 (03) ◽  
pp. 256-258
Author(s):  
Ken-ichi Tanaka ◽  
Takeshi Nanba ◽  
Tomoyuki Furubayashi ◽  
Yasuko Noda ◽  
Luther James Willmore ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Molecular Basis ◽  
Scavenging Effect

scholarly journals Radical Scavenging Activities of Novel Cationic Inulin Derivatives

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1295
Author(s):  
Yuan Chen ◽  
Yingqi Mi ◽  
Jingjing Zhang ◽  
Fang Dong ◽  
Qing Li ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Synthesis Process ◽  
Scavenging Activity ◽  
Scavenging Effect ◽  
Radical Scavenging Effect ◽  
Ft Ir

Many saccharides are attractive targets for biomaterial applications, due to their abundance, biocompatibility, and biodegradability. In this article, a synthesis process of 6-N-substituted cationic inulin derivatives, including 6-pyridyl-6-deoxyinulin bromide (PIL), 6-(2-amino-pyridyl)-6-deoxyinulin bromide (2APIL), 6-(3-amino-pyridyl)-6-deoxyinulin bromide (3APIL), 6-(4-amino-pyridyl)-6-deoxyinulin bromide (4APIL), 6-(2,3-diamino-pyridyl)-6-deoxyinulin bromide (2,3DAPIL), 6-(3,4-diamino-pyridyl)-6-deoxyinulin bromide (3,4DAPIL), and 6-(2,6-diamino-pyridyl)-6-deoxyinulin bromide (2,6DAPIL) was described. The C6-OH of inulin was first activated by PPh3/N-bromosuccinimide (NBS) bromination. Then, pyridine and different kinds of amino-pyridine groups (different position and different numbers of amino) were grafted onto inulin, respectively, via nucleophilic substitution. Then, we confirmed their structure by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. After this, their radical scavenging activities against hydroxyl radical and diphenylpicryl phenylhydrazine (DPPH) radical were tested in vitro. Each derivative showed a distinct improvement in radical scavenging activity when compared to inulin. The hydroxyl-radical scavenging effect decreased in the following order: 3APIL > PIL > 3,4DAPIL > 4APIL > 2,3DAPIL > 2,6DAPIL > 2APIL. Amongst them, 3APIL revealed the most powerful scavenging effect on hydroxyl radicals, as well as DPPH radicals. At 1.6 mg/mL, it could completely eliminate hydroxyl radicals and could clear 65% of DPPH radicals. The results also showed that the steric hindrance effect and the substitute position of the amino group had an effect on the radical scavenging activity. Moreover, the application prospects of inulin derivatives as natural antioxidant biomaterials are scientifically proven in this paper.

Molecular Basis of Iterative C–H Oxidation by TamI, a Multifunctional P450 Monooxygenase from the Tirandamycin Biosynthetic Pathway

2020 ◽  
Author(s):  
Sean A. Newmister ◽  
Kinshuk Raj Srivastava ◽  
Rosa V. Espinoza ◽  
Kersti Caddell Haatveit ◽  
Yogan Khatri ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Molecular Basis ◽  
Hydrophobic Interactions ◽  
Cytochromes P450 ◽  
Targeted Mutagenesis ◽  
P450 Monooxygenase ◽  
Bond Functionalization ◽  
Dynamics Simulations

Biocatalysis offers an expanding and powerful strategy to construct and diversify complex molecules by C-H bond functionalization. Due to their high selectivity, enzymes have become an essential tool for C-H bond functionalization and offer complementary reactivity to small-molecule catalysts. Hemoproteins, particularly cytochromes P450, have proven effective for selective oxidation of unactivated C-H bonds. Previously, we reported the in vitro characterization of an oxidative tailoring cascade in which TamI, a multifunctional P450 functions co-dependently with the TamL flavoprotein to catalyze regio- and stereoselective hydroxylations and epoxidation to yield tirandamycin A and tirandamycin B. TamI follows a defined order including 1) C10 hydroxylation, 2) C11/C12 epoxidation, and 3) C18 hydroxylation. Here we present a structural, biochemical, and computational investigation of TamI to understand the molecular basis of its substrate binding, diverse reactivity, and specific reaction sequence. The crystal structure of TamI in complex with tirandamycin C together with molecular dynamics simulations and targeted mutagenesis suggest that hydrophobic interactions with the polyene chain of its natural substrate are critical for molecular recognition. QM/MM calculations and molecular dynamics simulations of TamI with variant substrates provided detailed information on the molecular basis of sequential reactivity, and pattern of regio- and stereo-selectivity in catalyzing the three-step oxidative cascade.<br>

scholarly journals Assembly of the B subunit pentamer of Escherichia coli heat-labile enterotoxin. Kinetics and molecular basis of rate-limiting steps in vitro.

1996 ◽  
Vol 271 (43) ◽  
pp. 27188
Author(s):  
Lloyd W. Ruddock ◽  
Jeremy J.F. Coen ◽  
Caroline Cheesman ◽  
Robert B. Freedman ◽  
Timothy R. Hirst
Keyword(s):  
Escherichia Coli ◽  
Molecular Basis ◽  
B Subunit ◽  
Heat Labile ◽  
Rate Limiting

The scavenging effect of curcumin, piperine and their combination against physiological relevant reactive pro-oxidant species using in vitro non-cellular and cellular models

2021 ◽  
Author(s):  
Mariana Lucas ◽  
Marisa Freitas ◽  
Jadriane A. Xavier ◽  
Fabiana A. Moura ◽  
Marília O. F. Goulart ◽  
...  
Keyword(s):  
Scavenging Effect ◽  
Cellular Models

Effect of zinc on superoxide-dependent hydroxyl radical production in vitro

1993 ◽  
Vol 38 (3) ◽  
pp. 273-287 ◽  
Author(s):  
C. Coudray ◽  
S. Rachidi ◽  
A. Favier
Keyword(s):  
Hydroxyl Radical ◽  
Radical Production

Isolation of polypeptides with microtubule-translocating activity from phragmoplasts of tobacco BY-2 cells

1994 ◽  
Vol 107 (8) ◽  
pp. 2249-2257 ◽  
Author(s):  
T. Asada ◽  
H. Shibaoka
Keyword(s):  
Motor Activity ◽  
Molecular Basis ◽  
Plant Cells ◽  
Cell Plate ◽  
Gtpase Activity ◽  
High Concentration ◽  
Higher Plant ◽  
Main Components ◽  
Brain Tubulin

As part of our efforts to understand the molecular basis of the microtubule-associated motility that is involved in cytokinesis in higher plant cells, an attempt was made to identify proteins with the ability to translocate microtubules in an extract from isolated phragmoplasts. Homogenization of isolated phragmoplasts in a solution that contained MgATP, MgGTP and a high concentration of NaCl resulted in the release from phragmoplasts of factors with ATPase and GTPase activity that were stimulated by microtubules. A protein fraction with microtubule-dependent ATPase and GTPase activity caused minus-end-headed gliding of microtubules in the presence of ATP or GTP. Polypeptides with microtubule-translocating activity cosedimented with microtubules that had been assembled in vitro from brain tubulin and were dissociated from sedimented microtubules by addition of ATP or GTP. After cosedimentation and dissociation procedures, a 125 kDa polypeptide and a 120 kDa polypeptide were recovered in a fraction that supported minus-end-headed gliding of microtubules. The rate of microtubule gliding that was caused by the fraction that contained the 125 kDa and 120 kDa polypeptides as main components was 1.28 microns/minute in the presence of ATP and 0.50 microns/minute in the presence of GTP. This fraction contained some microtubule-associated polypeptides in addition to the 125 kDa and 120 kDa polypeptides, but a fraction that contained only these additional polypeptides did not cause any translocation of microtubules. Thus, it appeared that the 125 kDa and 120 kDa polypeptides were responsible for translocation of microtubules. These polypeptides with plus-end-directed motor activity may play an important role in formation of the cell plate and in the organization of the phragmoplast.

scholarly journals Qualities of Native Apple Cultivar Juices Characteristic of Central Europe

2012 ◽  
Vol 40 (1) ◽  
pp. 222 ◽  
Author(s):  
Otakar ROP ◽  
Martin POSOLDA ◽  
Jiri MLCEK ◽  
Vojtech REZNICEK ◽  
Jiri SOCHOR ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Ascorbic Acid ◽  
Hydroxyl Radical ◽  
Antioxidant Capacity ◽  
Antioxidant Properties ◽  
Landscape Management ◽  
Ascorbic Acid Content ◽  
Fruit Trees ◽  
Apple Fruit ◽  
Scavenging Effect

During the last century due to the changes in landscape management, in country people’s lives and with intensive fruit-growing the native cultivars of apple fruit trees have been gradually disappearing. The aim of the study was to compare the juices made of native apple cider cultivars. The cultivars-‘Boikovo’, ‘Jadernicka moravska’, ‘Kardinal zihany’, ‘Panenske ceske’, ‘Parmena zlata zimni’, ‘Strymka’ growing in the locality of the Litencicke Hills in the eastern part of the Czech Republic were selected. For comparison, the fruits of commercial ‘Idared’ cultivar were also included. The chemical composition, antioxidant capacity, phenols, flavonoids and ascorbic acid content and the influence of juices on scavenging activity of nitric oxide and hydroxyl radical were measured. The mutual ratio of examined properties which were found, provide information about qualities and possibilities of use of native cultivars. High antioxidant properties characterize the juice of native apple cultivars. In particular, the ‘Strymka’ cultivar contained 2,637.34 mg of AAE (ascorbic acid equivalent) per litre in case of antioxidant capacity. In the juice of this cultivar the value of 144.05 mg of ascorbic acid per litre was recorded. As regards the ‘Panenske ceske’ cultivar, antioxidant capacity was 2,548.38 mg of AAE l-1 and in relation to ascorbic acid, the value was 145.35 mg l-1. Similarly, high values were observed in both cultivars concerning the scavenging effect of apple juices on hydroxyl radical and nitric oxide (the ‘Strymka’ cultivar 16.38% and 19.26%, the ‘Panenske ceske’ cultivar 16.31% and 18.60%).

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