Role of Desorption Kinetics in Determining Marangoni Flows Generated by Using Electrochemical Methods and Redox-Active Surfactants

Langmuir ◽  
2005 ◽  
Vol 21 (6) ◽  
pp. 2235-2241 ◽  
Author(s):  
Guiyu Bai ◽  
Michael D. Graham ◽  
Nicholas L. Abbott
Keyword(s):  
Electrochemical Methods ◽  
Desorption Kinetics ◽  
Redox Active ◽  
Marangoni Flows

Recent Progress in the Analysis of Captopril Using Electrochemical Methods: A Review

2019 ◽  
Vol 15 (3) ◽  
pp. 198-206 ◽  
Author(s):  
Sarfaraz Ahmed Mahesar ◽  
Saeed Ahmed Lakho ◽  
Syed Tufail Hussain Sherazi ◽  
Hamid Ali Kazi ◽  
Kamran Ahmed Abro ◽  
...  
Keyword(s):  
Enzyme Inhibitor ◽  
Modified Electrodes ◽  
High Sensitivity ◽  
Pharmaceutical Formulations ◽  
Inorganic Materials ◽  
Electrochemical Methods ◽  
Nano Particles ◽  
Moderate Heart Failure ◽  
Analytical Instrumentation

Background: Captopril is the synthetic dipeptide used as an angiotensin converting enzyme inhibitor. Captopril is used to treat hypertension as well as for the treatment of moderate heart failure. Analytical instrumentation and methodology plays an important role in pharmaceutical analysis. Methods: This review presents some important applications of electrochemical modes used for the analysis of captopril. So far captopril has been analyzed by using different bare and modified working electrodes with a variety of modifiers from organic and inorganic materials to various types of nano particles/materials. Results: This paper presents some of the methods which have been published in the last few years i.e. from 2003 to 2016. This review highlights the role of the analytical instrumentation, particularly electrochemical methods in assessing captopril using various working electrodes. Conclusion: A large number of studies on voltammetry noted by means of various bare and modified electrodes. Among all of the published voltammetric methods, DPV, SWV, CV and miscellaneous modes were trendy techniques used to analyze captopril in pharmaceutical formulations as well as biological samples. Electrodes modified with nanomaterials are promising sensing tools as this showed high sensitivity, good accuracy with precision as well as selectivity. In comparison to chromatographic methods, the main advantages of electrochemical methods are its cheaper instrumentation, lower detection limit and minimal or no sample preparation.

scholarly journals Electrochemical Methods and (Bio) Sensors for Rosmarinic Acid Investigation

Chemosensors ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 74
Author(s):  
Iulia Gabriela David ◽  
Dana Elena Popa ◽  
Mihaela Buleandră ◽  
Mihaela Carmen Cheregi
Keyword(s):  
Antioxidant Activity ◽  
Dynamic Systems ◽  
Phenolic Acid ◽  
Rosmarinic Acid ◽  
Electrochemical Methods ◽  
Redox Active ◽  
Polyphenolic Content ◽  
Total Polyphenolic Content ◽  
Electroactive Species ◽  
Electrochemical Methods Of Analysis

Rosmarinic acid (RA) is an important bioactive phenolic acid with significant biochemical activities, including the antioxidant one. It is widely found in plants of the families Lamiaceae and Boraginaceae and has many uses in the food, pharmaceutical and cosmetics industries. RA is an electroactive species owing to the presence of the two catechol groups in its structure. Due to their inherent characteristics, such as sensitivity, selectivity, ease of operation and not too high costs, electrochemical methods of analysis are interesting tools for the assessment of redox-active compounds. Moreover, there is a good correlation between the redox potential of the analyte and its capability to donate electrons and, consequently, its antioxidant activity. Therefore, this paper presents a detailed overview of the electrochemical (bio)sensors and methods, in both stationary and dynamic systems, applied for RA investigation under different aspects. These comprise its antioxidant activity, its interaction with biological important molecules and the quantification of RA or total polyphenolic content in different samples.

The role of cardiomyocyte Nox4D, a redox-active splice variant of NADPH oxidase-4

2018 ◽  
Vol 120 ◽  
pp. 20
Author(s):  
N. Savage ◽  
N. Anilkumar ◽  
E. Henckaerts ◽  
A.M. Shah
Keyword(s):  
Nadph Oxidase ◽  
Splice Variant ◽  
Nadph Oxidase 4 ◽  
Redox Active

scholarly journals Characterization of the endoplasmic reticulum–resident peroxidases GPx7 and GPx8 shows the higher oxidative activity of GPx7 and its linkage to oxidative protein folding

2020 ◽  
Vol 295 (36) ◽  
pp. 12772-12785 ◽  
Author(s):  
Shingo Kanemura ◽  
Elza Firdiani Sofia ◽  
Naoya Hirai ◽  
Masaki Okumura ◽  
Hiroshi Kadokura ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Folding ◽  
Physiological Role ◽  
High Reactivity ◽  
Oxidation Activity ◽  
Formation Pathway ◽  
Oxidative Protein Folding ◽  
Redox Active ◽  
Protein Disulfide

Oxidative protein folding occurs primarily in the mammalian endoplasmic reticulum, enabled by a diverse network comprising more than 20 members of the protein disulfide isomerase (PDI) family and more than five PDI oxidases. Although the canonical disulfide bond formation pathway involving Ero1α and PDI has been well-studied so far, the physiological roles of the newly identified PDI oxidases, glutathione peroxidase-7 (GPx7) and -8 (GPx8), are only poorly understood. We here demonstrated that human GPx7 has much higher reactivity with H2O2 and hence greater PDI oxidation activity than human GPx8. The high reactivity of GPx7 is due to the presence of a catalytic tetrad at the redox-active site, which stabilizes the sulfenylated species generated upon the reaction with H2O2. Although it was previously postulated that GPx7 catalysis involved a highly reactive peroxidatic cysteine that can be sulfenylated by H2O2, we revealed that a resolving cysteine instead regulates the PDI oxidation activity of GPx7. We also determined that GPx7 formed complexes preferentially with PDI and P5 in H2O2-treated cells. Altogether, these results suggest that human GPx7 functions as an H2O2-dependent PDI oxidase in cells, whereas PDI oxidation may not be the central physiological role of human GPx8.

scholarly journals Sulfur-centered hemi-bond radicals as active intermediates in S-DNA phosphorothioate oxidation

2019 ◽  
Author(s):  
Jialong Jie ◽  
Ye Xia ◽  
Chun-Hua Huang ◽  
Hongmei Zhao ◽  
Chunfan Yang ◽  
...  
Keyword(s):  
Bacterial Genome ◽  
Protective Role ◽  
Hole Transfer ◽  
Time Resolved ◽  
Dna Lesion ◽  
Chemical Effects ◽  
Redox Active ◽  
Underlying Mechanisms ◽  
Active Intermediates

Abstract Phosphorothioate (PS) modifications naturally appear in bacteria and archaea genome and are widely used as antisense strategy in gene therapy. But the chemical effects of PS introduction as a redox active site into DNA (S-DNA) is still poorly understood. Herein, we perform time-resolved spectroscopy to examine the underlying mechanisms and dynamics of the PS oxidation by potent radicals in free model, in dinucleotide, and in S-oligomer. The crucial sulphur-centered hemi-bonded intermediates -P–S∴S–P- were observed and found to play critical roles leading to the stable adducts of -P–S–S–P-, which are backbone DNA lesion products. Moreover, the oxidation of the PS moiety in dinucleotides d[GPSG], d[APSA], d[GPSA], d[APSG] and in S-oligomers was monitored in real-time, showing that PS oxidation can compete with adenine but not with guanine. Significantly, hole transfer process from A+• to PS and concomitant -P–S∴S–P- formation was observed, demonstrating the base-to-backbone hole transfer unique to S-DNA, which is different from the normally adopted backbone-to-base hole transfer in native DNA. These findings reveal the distinct backbone lesion pathway brought by the PS modification and also imply an alternative -P–S∴S–P-/-P–S–S–P- pathway accounting for the interesting protective role of PS as an oxidation sacrifice in bacterial genome.

scholarly journals Mapping hole hopping escape routes in proteins

2019 ◽  
Vol 116 (32) ◽  
pp. 15811-15816 ◽  
Author(s):  
Ruijie D. Teo ◽  
Ruobing Wang ◽  
Elizabeth R. Smithwick ◽  
Agostino Migliore ◽  
Michael J. Therien ◽  
...  
Keyword(s):  
Oxidative Damage ◽  
Protective Role ◽  
Residence Times ◽  
P450 Monooxygenase ◽  
Protection Mechanism ◽  
Biologically Relevant ◽  
Redox Active ◽  
Catalytic Sites ◽  
Benzylsuccinate Synthase

A recently proposed oxidative damage protection mechanism in proteins relies on hole hopping escape routes formed by redox-active amino acids. We present a computational tool to identify the dominant charge hopping pathways through these residues based on the mean residence times of the transferring charge along these hopping pathways. The residence times are estimated by combining a kinetic model with well-known rate expressions for the charge-transfer steps in the pathways. We identify the most rapid hole hopping escape routes in cytochrome P450 monooxygenase, cytochrome c peroxidase, and benzylsuccinate synthase (BSS). This theoretical analysis supports the existence of hole hopping chains as a mechanism capable of providing hole escape from protein catalytic sites on biologically relevant timescales. Furthermore, we find that pathways involving the [4Fe4S] cluster as the terminal hole acceptor in BSS are accessible on the millisecond timescale, suggesting a potential protective role of redox-active cofactors for preventing protein oxidative damage.

scholarly journals Iron Redox Chemistry and Implications in the Parkinson’s Disease Brain

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Dinendra L. Abeyawardhane ◽  
Heather R. Lucas
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Iron Homeostasis ◽  
Substantia Nigra Pars Compacta ◽  
Biochemical Alterations ◽  
Redox Active ◽  
Cellular Inclusions ◽  
Iron Redox ◽  
Presynaptic Protein

The etiology of Parkinson’s disease (PD) is linked with cellular inclusions in the substantia nigra pars compacta region of the brain that are enriched in the misfolded presynaptic protein α-synuclein (αS) and death of the dopaminergic neurons. Brain iron homeostasis governs both neurotransmission and neurodegeneration; hence, the role of iron in PD progression and neuronal health is apparent. Elevated iron deposits become prevalent in the cerebral region upon aging and even more so in the PD brain. Structural as well as oxidative modifications can result from coordination of αS with redox active iron, which could have functional and/or pathological implications. In this review, we will discuss iron-mediated αS aggregation, alterations in iron metabolism, and the role of the iron-dopamine couple. Moreover, iron interactions with N-terminally acetylated αS, the physiologically relevant form of the human protein, will be addressed to shed light on the current understanding of protein dynamics and the physiological environment in the disease state. Oxidative pathways and biochemical alterations resulting from aberrant iron-induced chemistry are the principal focus of this review in order to highlight the plethora of research that has uncovered this emerging dichotomy of iron playing both functional and disruptive roles in PD pathology.

scholarly journals Pathological consequences of the unfolded protein response and downstream protein disulphide isomerases in pulmonary viral infection and disease

2019 ◽  
Vol 167 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Nicolas Chamberlain ◽  
Vikas Anathy
Keyword(s):  
Unfolded Protein Response ◽  
Unfolded Protein ◽  
Disease States ◽  
Redox Active ◽  
Complex Adaptive ◽  
Bond Rearrangement ◽  
The Individual ◽  
The Unfolded Protein Response ◽  
Protein Response

Abstract Protein folding within the endoplasmic reticulum (ER) exists in a delicate balance; perturbations of this balance can overload the folding capacity of the ER and disruptions of ER homoeostasis is implicated in numerous diseases. The unfolded protein response (UPR), a complex adaptive stress response, attempts to restore normal proteostasis, in part, through the up-regulation of various foldases and chaperone proteins including redox-active protein disulphide isomerases (PDIs). There are currently over 20 members of the PDI family each consisting of varying numbers of thioredoxin-like domains which, generally, assist in oxidative folding and disulphide bond rearrangement of peptides. While there is a large amount of redundancy in client proteins of the various PDIs, the size of the family would indicate more nuanced roles for the individual PDIs. However, the role of individual PDIs in disease pathogenesis remains uncertain. The following review briefly discusses recent findings of ER stress, the UPR and the role of individual PDIs in various respiratory disease states.

Role of Redox Active Ligand of a Cobalt-Mabiq Complex in the Hydrogen Evolution Reaction

2020 ◽  
Vol MA2020-02 (43) ◽  
pp. 2760-2760
Author(s):  
Guelen Ceren Tok ◽  
Anna Teresa Sophie Freiberg ◽  
Leonhard Reinschlüssel ◽  
Hubert A. Gasteiger ◽  
Corinna R Hess
Keyword(s):  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Redox Active Ligand ◽  
Active Ligand ◽  
Redox Active
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