Scavenging of hydrated electron by HSA or Ligand/HSA adduct: Pulse radiolysis study

Konarska, Anna; Radomska, Karolina; Wolszczak, Marian

doi:10.1016/j.radphyschem.2018.07.003

Cited by 9 publications

(7 citation statements)

References 38 publications

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“…It is less likely that the OH radical will reach Trp 214 and will react but not oxidize the tryptophan moiety. Referring to our earlier work [ 54 ] in which we showed that the hydrated electron does not reach the Sudlow 1 site, it can be concluded that this densely packed and hydrophobic domain is not directly exposed to radical attack. We noticed that which is assigned to the TyrO • radical is formed in a longer time scale after the OH radical reaction with HSA (TyrO • band is visible in the HSA spectrum after 170 µs after the electron pulse; see Figure S7 ).…”

Section: Resultssupporting

confidence: 60%

“…By using different oxidizing radicals in our pulsed radiolysis measurements, we can expect that certain aromatic groups of HSA will be more readily available for attack by the radical. In our publication on the reaction of reducing radicals (

, H • ,

) with HSA, we have shown that the Sudlow 1 site, and in particular Trp214 located here, is well protected against these radicals [ 54 ]. Additionally, by generating radicals with different redox potential, we can to some extent decide which of the aromatic residues will be involved in the radical scavenging.…”

Section: Resultsmentioning

confidence: 99%

“…The dose could be varied over a wide range from 10 (pulse duration 7 ns) to 60 Gy. The dose was determined for each measurement series using water [ 54 ] or thiocyanate as a dosimeter. We also used two different pulses with a duration of 1 or 4 µs.…”

Section: Methodsmentioning

confidence: 99%

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Spontaneous and Ionizing Radiation-Induced Aggregation of Human Serum Albumin: Dityrosine as a Fluorescent Probe

Radomska

Wolszczak

2022

IJMS

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The use of spectroscopic techniques has shown that human serum albumin (HSA) undergoes reversible self-aggregation through protein–protein interactions. It ensures the subsequent overlapping of electron clouds along with the stiffening of the conformation of the interpenetrating network of amino acids of adjacent HSA molecules. The HSA oxidation process related to the transfer of one electron was investigated by pulse radiolysis and photochemical methods. It has been shown that the irradiation of HSA solutions under oxidative stress conditions results in the formation of stable protein aggregates. The HSA aggregates induced by ionizing radiation are characterized by specific fluorescence compared to the emission of non-irradiated solutions. We assume that HSA dimers are mainly responsible for the new emission. Dityrosine produced by the intermolecular recombination of protein tyrosine radicals as a result of radiolysis of an aqueous solution of the protein is the main cause of HSA aggregation by cross-linking. Analysis of the oxidation process of HSA confirmed that the reaction of mild oxidants (Br2•−, N3•, SO4•−) with albumin leads to the formation of covalent bonds between tyrosine residues. In the case of •OH radicals and partly, Cl2•−, species other than DT are formed. The light emission of this species is similar to the emission of self-associated HSA.

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Section: Resultssupporting

confidence: 60%

, H • ,

Section: Resultsmentioning

confidence: 99%

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Spontaneous and Ionizing Radiation-Induced Aggregation of Human Serum Albumin: Dityrosine as a Fluorescent Probe

Radomska

Wolszczak

2022

IJMS

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“…As shown in Figure 5, transient species with maximum absorption at 320 nm swiftly increased in saturation of N 2 and decreased in the presence of O 2 , which can be expected in that N 2 and O 2 are the protector and scavenger of the excited state, respectively. The transient species with an absorption band ranging from 500 to 800 nm was also able to be quenched by O 2 because of the e aq − (hydrated electron; Yuan et al 2012; Radomska et al 2018). In addition, an LFP experiment of the CAL solution containing 20% MeCN was conducted to further determine the properties of the compounds for the 500‐ to 800‐nm absorption peaks because e aq − can be quenched by MeCN (Singh et al 1968; Zhang et al 2012).…”

Section: Resultsmentioning

confidence: 99%

Insights into the Photodegradation of the Contact Allergen Fragrance Cinnamyl Alcohol: Kinetics, Mechanism, and Toxicity

Gao

Luo

et al. 2021

Enviro Toxic and Chemistry

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Fragrances can cause general health issues, and special concerns exist surrounding the issue of skin safety. Cinnamyl alcohol (CAL) is a frequent fragrance contact allergen that has various toxic effects on indiscriminate animals. In the present study, the photodegradation transformation mechanism of CAL and toxicity evolution during this process were examined. The results showed that CAL (50 μM) can be completely degraded after 90-min ultraviolet (UV) irradiation with a degradation rate of 0.086 min -1 . Increased toxicity on bioluminescent bacteria was observed during this process, with lethality increasing from 10.6% (0 min) to 50.2% (90 min) under UV light irradiation. Further, the photodegradation mechanisms of CAL were explored to find the reason behind the increased toxicity observed. Laser flash photolysis and quenching experiments showed that O 2•-, 1 O 2 , and • OH were mainly responsible for CAL photodegradation, together with 3 CAL* and e aq -. The 5 main photodegradation products were cinnamyl aldehyde, benzaldehyde, benzenepropanal, cinnamic acid, and toluene, as identified using gas chromatography-mass spectrometry and liquid chromatography-quadrupole-time-offlight-mass spectrometry. Once exposed to air, CAL was found to be easily oxidized to cinnamyl aldehyde and subsequently to cinnamic acid by O 2 •-or 1 O 2 -mediated pathways, leading to increased toxicity. Benzaldehyde exhibited bioreactive toxicity, increasing the toxicity through • OH-mediated pathways. Theoretical prediction of skin irritation indicated that cinnamyl aldehyde (0.83), benzenepropanal (0.69), cinnamyl aldehyde (0.69), and benzaldehyde (0.70) were higher than CAL (0.63), which may cause a profound impact on an individual's health and well-being. Overall, the present study advances the understanding of the photodegradation processes and health impacts of fragrance ingredients.

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“…complex. It has been claimed [ 64 ] that ligands located at the Sudlow’s site 1 are not reduced by the hydrated electron. We found that Py-LYQLENY ( 2 ) is efficiently reduced by hydrated electron in a buffer solution even in concentration as low as 20 µM ( Figure S10 ), while, in the presence of HSA, the reduction process of Py-LYQLENY has been completely eliminated.…”

Section: Resultsmentioning

confidence: 99%

Human Serum Albumin Binds Native Insulin and Aggregable Insulin Fragments and Inhibits Their Aggregation

et al. 2020

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The purpose of this study was to investigate whether Human Serum Albumin (HSA) can bind native human insulin and its A13–A19 and B12–B17 fragments, which are responsible for the aggregation of the whole hormone. To label the hormone and both hot spots, so that their binding positions within the HSA could be identified, 4-(1-pyrenyl)butyric acid was used as a fluorophore. Triazine coupling reagent was used to attach the 4-(1-pyrenyl)butyric acid to the N-terminus of the peptides. When attached to the peptides, the fluorophore showed extended fluorescence lifetimes in the excited state in the presence of HSA, compared to the samples in buffer solution. We also analyzed the interactions of unlabeled native insulin and its hot spots with HSA, using circular dichroism (CD), the microscale thermophoresis technique (MST), and three independent methods recommended for aggregating peptides. The CD spectra indicated increased amounts of the α-helical secondary structure in all analyzed samples after incubation. Moreover, for each of the two unlabeled hot spots, it was possible to determine the dissociation constant in the presence of HSA, as 14.4 µM (A13–A19) and 246 nM (B12–B17). Congo Red, Thioflavin T, and microscopy assays revealed significant differences between typical amyloids formed by the native hormone or its hot-spots and the secondary structures formed by the complexes of HSA with insulin and A13–A19 and B12–B17 fragments. All results show that the tested peptide-probe conjugates and their unlabeled analogues interact with HSA, which inhibits their aggregation.

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Scavenging of hydrated electron by HSA or Ligand/HSA adduct: Pulse radiolysis study

Cited by 9 publications

References 38 publications

Spontaneous and Ionizing Radiation-Induced Aggregation of Human Serum Albumin: Dityrosine as a Fluorescent Probe

Spontaneous and Ionizing Radiation-Induced Aggregation of Human Serum Albumin: Dityrosine as a Fluorescent Probe

Insights into the Photodegradation of the Contact Allergen Fragrance Cinnamyl Alcohol: Kinetics, Mechanism, and Toxicity

Human Serum Albumin Binds Native Insulin and Aggregable Insulin Fragments and Inhibits Their Aggregation

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