scholarly journals Partial Reactivities Observed in the Hydrogen Abstraction Reactions of Hydroxyl Radicals from Aliphatic Amino Acids

1976 ◽  
Vol 17 (2) ◽  
pp. 63-68 ◽  
Author(s):  
T. MASUDA ◽  
S. NAKANO ◽  
K. YOSHIHARA ◽  
M. KONDO
Keyword(s):  
Amino Acids ◽  
Hydroxyl Radicals ◽  
Hydrogen Abstraction

γ-Radiation-induced carboxylation of pyrrolidine

1976 ◽  
Vol 29 (12) ◽  
pp. 2603 ◽  
Author(s):  
A Davison ◽  
NT Barker ◽  
DF Sangster
Keyword(s):  
Aqueous Solution ◽  
Amino Acids ◽  
Carboxylic Acid ◽  
Hydroxyl Radicals ◽  
Hydrogen Abstraction ◽  
Major Product ◽  
Amino Group ◽  
Γ Radiation ◽  
Neutral Aqueous Solution ◽  
Radiation Induced

Amino acids produced in the γ-radiation-induced carboxylation of pyrrolidine and formate in neutral aqueous solution have been studied. Two products only were found in the ratio 1 : 5.5. The minor product, proline, and the major product, pyrrolidine-3-carboxylic acid, have been characterized. Their presence indicates that the predominant site of hydrogen abstraction from pyrrolidine by radiation-generated hydroxyl radicals is β to the amino group.

The isomeric distribution of amino acids produced in γ-radiolytic carboxylation of amines

1977 ◽  
Vol 30 (4) ◽  
pp. 807
Author(s):  
A Davison ◽  
NT Barker ◽  
DF Sangster
Keyword(s):  
Amino Acids ◽  
Hydroxyl Radicals ◽  
Hydrogen Abstraction ◽  
Γ Radiation ◽  
Factors Influencing ◽  
Yield Information ◽  
Isomeric Distribution

Amino acids produced in the γ-radiation-initiated carboxylation of ethylamine, propylamine, isopropylamine, butane-1,4-diamine and pyrrolidine have been characterized. Isomeric distributions of amino acids from each amine have been determined. These distributions reflect the isomeric distribution of amine radicals present, and hence yield information on the initial site of hydrogen abstraction by radiolytically generated hydroxyl radicals. Factors influencing the sites of abstraction are discussed.

FREE RADICALS OF BIOLOGICAL INTEREST: PART II. ELECTRON SPIN RESONANCE (ESR) SPECTRA OF 2537 A IRRADIATED AMINO ACIDS

1967 ◽  
Vol 45 (12) ◽  
pp. 1831-1839 ◽  
Author(s):  
W. F. Forbes ◽  
P. D. Sullivan
Keyword(s):  
Amino Acids ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Hydrogen Abstraction ◽  
Esr Spectra ◽  
Side Chain ◽  
Biological Interest ◽  
Spin Resonance ◽  
Cyclohexadienyl Radical ◽  
Secondary Radical

Polycrystalline amino acids, when irradiated with 2537 Å light, afford a variety of electron spin resonance signals. These signals are generally stable at room temperature for relatively long periods of time. For a number of the spectra obtained, there is evidence that more than one radical species contributes to the observed spectra. The signals obtained frequently differ from those obtained on exposure to ionizing radiation. The postulated species formed can often be visualized as being formed by effective hydrogen abstraction from the alkyl-substituted tertiary carbon atom or from the —OH, —SH or —NH group contained in the side chain. For L-phenylalanine a secondary radical is obtained, which is ascribed to a cyclohexadienyl radical.

Theoretical Study of the Kinetics of the Hydrogen Abstraction from Methanol. 3. Reaction of Methanol with Hydrogen Atom, Methyl, and Hydroxyl Radicals

1999 ◽  
Vol 103 (19) ◽  
pp. 3750-3765 ◽  
Author(s):  
Jerzy T. Jodkowski ◽  
Marie-Thérèse Rayez ◽  
Jean-Claude Rayez ◽  
Tibor Bérces ◽  
Sándor Dóbé
Keyword(s):  
Hydrogen Atom ◽  
Hydroxyl Radicals ◽  
Theoretical Study ◽  
Hydrogen Abstraction ◽  
Kinetics Of

scholarly journals An E.S.R study of the oxidation of sodium alkyl sulphates by hydroxyl radicals

1977 ◽  
Vol 30 (3) ◽  
pp. 695 ◽  
Author(s):  
FR Hewgill ◽  
GM Proudfoot
Keyword(s):  
Electron Spin Resonance ◽  
Carboxylic Acids ◽  
Hydroxyl Radicals ◽  
Electron Spin ◽  
Hydrogen Abstraction ◽  
Spin Resonance ◽  
Aliphatic Carboxylic Acids ◽  
H2o2 System

Radicals detected by electron spin resonance show that hydrogen abstraction in the oxidation of alkyl sulphates by the TiCl3/H2O2 system is not selective. In the light of these results and of evidence obtained by reduction of γ-iodocaproic acid, the previous claim1 that hydrogen abstraction from aliphatic carboxylic acids containing 6-8 carbons occurs chiefly at the α and ω-1 position scan no longer be supported.

scholarly journals Reaction of Br3·2- with 2-Deoxy-D-ribose. A Preferred Attack at C-1

1978 ◽  
Vol 33 (6) ◽  
pp. 666-668 ◽  
Author(s):  
Barry J. Parsons ◽  
Dietrich Schulte-Frohlinde ◽  
Clemens von Sonntag
Keyword(s):  
Aqueous Solutions ◽  
Hydroxyl Radicals ◽  
Pulse Radiolysis ◽  
Hydrogen Abstraction ◽  
Major Product ◽  
Alternative Route ◽  
Sugar Moiety ◽  
Bromide Ions

Abstract In the photolysis of 5-bromouracil containing DNA Br atoms are expected inter mediates. In order to evaluate the possible site of attack of the Br atom at the sugar moiety of DNA the reaction of 2-deoxy-D-ribose with the Br atom (complexed with two bromide ions) was investigated. Hydroxyl radicals generated by the radiolysis of N2O saturated aqueous solutions were converted into Br3·2- radicals by 1 M bromide ions. Br3·2- reacts with 2-deoxy-D-ribose (k = 3.7 · 104M-1s-1, pulse radiolysis). The major product is 2-deoxy-D-erythro-pentonic acid (G = 2.4, γ-radiolysis). It is formed by hydrogen abstraction from C-l and oxidation of this radical by other radicals. An alternative route via the radical at C-2 is neglible. It follows that Br3·2- reacts preferentially at C-1 of 2-deoxy-D-ribose

scholarly journals The Impact of Capsid Proteins on Virus Removal and Inactivation during Water Treatment Processes

2015 ◽  
Vol 8s2 ◽  
pp. MBI.S31441 ◽  
Author(s):  
Brooke K. Mayer ◽  
Yu Yang ◽  
Daniel W. Gerrity ◽  
Morteza Abbaszadegan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Hydroxyl Radicals ◽  
Capsid Proteins ◽  
Virus Inactivation ◽  
Virus Removal ◽  
Titanium Dioxide Photocatalysis ◽  
Genomic Damage ◽  
Virus Size ◽  
The Impact

This study examined the effect of the amino acid composition of protein capsids on virus inactivation using ultraviolet (UV) irradiation and titanium dioxide photocatalysis, and physical removal via enhanced coagulation using ferric chloride. Although genomic damage is likely more extensive than protein damage for viruses treated using UV, proteins are still substantially degraded. All amino acids demonstrated significant correlations with UV susceptibility. The hydroxyl radicals produced during photocatalysis are considered nonspecific, but they likely cause greater overall damage to virus capsid proteins relative to the genome. Oxidizing chemicals, including hydroxyl radicals, preferentially degrade amino acids over nucleotides, and the amino acid tyrosine appears to strongly influence virus inactivation. Capsid composition did not correlate strongly to virus removal during physicochemical treatment, nor did virus size. Isoelectric point may play a role in virus removal, but additional factors are likely to contribute.

scholarly journals α-Hydrogen Abstraction by •OH and •SH Radicals from Amino Acids and Their Peptide Derivatives

2016 ◽  
Vol 12 (4) ◽  
pp. 1606-1613 ◽  
Author(s):  
Bun Chan ◽  
Amir Karton ◽  
Christopher J. Easton ◽  
Leo Radom
Keyword(s):  
Amino Acids ◽  
Hydrogen Abstraction ◽  
Peptide Derivatives

scholarly journals The Reactions of Hydroxyl Radicals with 1,4-and 1,3-Cyclohexadiene in Aqueous Solution

1988 ◽  
Vol 43 (9) ◽  
pp. 1201-1205 ◽  
Author(s):  
Xian-Ming Pan ◽  
Eugenie Bastian ◽  
Clemens von Sonntag
Keyword(s):  
Hydroxyl Radicals ◽  
Pulse Radiolysis ◽  
Hydrogen Abstraction ◽  
Material Balance ◽  
Oh Radicals ◽  
Oh Radical ◽  
Product Analysis ◽  
Γ Irradiation ◽  
Abstraction Reaction ◽  
G Value

Abstract The reactions of radiolytically generated hydroxyl radicals and H atoms with 1,4- and 1,3-cyclohexadiene were studied by pulse radiolysis and product analysis. Hydrogen abstraction from these substrates by the OH radical yields the cyclohexadienyl radical (ε (310 nm) = 4400 dm3 mol-1 cm-1 from the reaction of the H atom with benzene) with an efficiency of 50% (0.29 ,μmol J-1) in the case of 1,4-cyclohexadiene and 25% (0.15 ,μmol J-1) in the case of 1,3-cyclohexadiene as determined by pulse radiolysis. The remaining OH radicals add to the olefin. In 1.4-cyclohexa- diene the yield of the resulting adduct radicals has been determined in a steady-state 60Co-γ-irradiation experiment by reducing it with added 1.4-dithiothreitol (DTT) to 4-hydroxycyc- lohexene. There are two sites of OH radical attack in the case of 1.3-cyclohexadiene, and only the alkyl radical is reduced quantitatively by DTT (G(3-hydroxycyclohexene) = 0.15 ,μmol J-1). From material balance considerations it is concluded that the allylic radical must be formed with a G value of 0.28 ,μmol J-1 but largelv escapes reduction by DTT (G(4-hvdroxycyclohexene) = 0.03 ,μmol J-1). H atoms add preferentially to the double bonds of 1,4- and 1,3-cyclohexadiene (78% and 93%, respectively), while the O.- radical (the basic form of the OH radical) undergoes mainly H- abstraction (92% and 83%, respectively). The radicals formed in these systems decay bimolecularly (2k = 2.8 x 109 dm3 mol-1 s-1). In their combination reactions the cyclohexadienyl radicals form the four possible dimers in propor­tions such that the dienyl radical moiety shows a 2:1 preference to react from its central (1a) rather than from a terminal carbon atom (1b). Cyclohexadienyl radicals and the OH- and H-adduct radicals also cross-tcrminate by disproportionation and dimerization. Material balance has been obtained for the 1,4-cyclohexadiene system in N2O-Saturated solution (10-2 mol dm-3) at a dose rate of 0.14 Gy s-1, the products (G values in ,μmol J-1) being: benzene (0.085), 4-hydroxycyclohexene (0.25), cyclohexadienyl-dimers (0.144). cvclohexadienyl-OH-adduct- dimers (0.02), OH-adduct-dimers (0.02). Some of the 4-hydroxycyclohcxene is formed in an H-abstraction reaction by the OH-adduct radical from 1,4-cyclohexadiene.

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