A novel nanoplatform encapsulating glucose oxidase for spectrophotometric biosensing of hydrogen peroxide and glucose

2020 ◽  
Vol 12 (3) ◽  
pp. 345-357
Author(s):  
Hamzeh Pezhhan ◽  
Morteza Akhond ◽  
Mojtaba Shamsipur
Keyword(s):  
Hydrogen Peroxide ◽  
Glucose Oxidase ◽  
Protein Interactions ◽  
Magnetic Nanoparticle ◽  
Marine Mussels

Inspired by the role of the chelation of Fe3+–catechol in inter-protein interactions and the production of adhesives by marine mussels, we used DA as an anchor to connect GOx to Fe3O4 magnetic nanoparticle cores via the formation of Fe(OH)3 shells.

METABOLISM OF MAMMALIAN ERYTHROCYTES: V. ROLE OF CATALASE IN THE OXIDATION OF RIBOSE-5-PHOSPHATE BY THE ERYTHROCYTE

1954 ◽  
Vol 32 (6) ◽  
pp. 644-654 ◽  
Author(s):  
Marc Francoeur ◽  
Orville F. Denstedt
Keyword(s):  
Hydrogen Peroxide ◽  
Methylene Blue ◽  
Glucose Oxidase ◽  
Anaerobic Conditions ◽  
Beef Liver ◽  
Aerobic Conditions

Ribose-5-phosphate has been found to be rapidly oxidized by the stroma-free hemolyzate of human, rat, and rabbit erythrocytes in the presence of ferricyanide under anaerobic conditions, or in the presence of methylene blue under aerobic conditions. Compounds resembling R-5-P, such as ribose, arabinose, xylose, glucose, glucose-6-phosphate, fructose-6-phosphate, and hexose diphosphate are not oxidized under these conditions. The oxidation does not involve DPN or TPN and it is completely inhibited by cyanide. The Ks is about 2 × 10−2 M. Under anaerobic conditions, in the presence of ferricyanide, the enzyme responsible for the oxidation is catalase. Purified catalase from beef liver or from rabbit erythrocytes yields the same results as the SFH from human, rat, or rabbit erythrocytes with respect to specificity, cyanide sensitivity, and the Ks value. Under aerobic conditions, catalase is responsible also for the oxidation of R-5-P, but the mechanism involves the peroxidase action of catalase. Catalase catalyzes the oxidation of R-5-P by hydrogen peroxide in the presence of a system which slowly generates hydrogen peroxide, such as the glucose–glucose oxidase or the hemoglobin – methylene blue systems.

METABOLISM OF MAMMALIAN ERYTHROCYTES: V. ROLE OF CATALASE IN THE OXIDATION OF RIBOSE-5-PHOSPHATE BY THE ERYTHROCYTE

1954 ◽  
Vol 32 (1) ◽  
pp. 644-654 ◽  
Author(s):  
Marc Francoeur ◽  
Orville F. Denstedt
Keyword(s):  
Hydrogen Peroxide ◽  
Methylene Blue ◽  
Glucose Oxidase ◽  
Anaerobic Conditions ◽  
Beef Liver ◽  
Aerobic Conditions

Ribose-5-phosphate has been found to be rapidly oxidized by the stroma-free hemolyzate of human, rat, and rabbit erythrocytes in the presence of ferricyanide under anaerobic conditions, or in the presence of methylene blue under aerobic conditions. Compounds resembling R-5-P, such as ribose, arabinose, xylose, glucose, glucose-6-phosphate, fructose-6-phosphate, and hexose diphosphate are not oxidized under these conditions. The oxidation does not involve DPN or TPN and it is completely inhibited by cyanide. The Ks is about 2 × 10−2 M. Under anaerobic conditions, in the presence of ferricyanide, the enzyme responsible for the oxidation is catalase. Purified catalase from beef liver or from rabbit erythrocytes yields the same results as the SFH from human, rat, or rabbit erythrocytes with respect to specificity, cyanide sensitivity, and the Ks value. Under aerobic conditions, catalase is responsible also for the oxidation of R-5-P, but the mechanism involves the peroxidase action of catalase. Catalase catalyzes the oxidation of R-5-P by hydrogen peroxide in the presence of a system which slowly generates hydrogen peroxide, such as the glucose–glucose oxidase or the hemoglobin – methylene blue systems.

Susceptibility to hydrogen peroxide ofPlasmodium falciparuminfecting glucose-6-phosphate dehydrogenase-deficient erythrocytes

Parasitology ◽  
1989 ◽  
Vol 99 (2) ◽  
pp. 171-174 ◽  
Author(s):  
S. Kamchonwongpaisan ◽  
A. Bunyaratvej ◽  
W. Wanachiwanawin ◽  
Y. Yuthavong
Keyword(s):  
Hydrogen Peroxide ◽  
Plasmodium Falciparum ◽  
Glucose Oxidase ◽  
Host Cells ◽  
Parasite Invasion ◽  
Killing Effect ◽  
Oxidase System ◽  
Relative Susceptibility ◽  
Glucose 6 Phosphate Dehydrogenase

SummaryThe susceptibility to oxidant-mediated killing ofPlasmodium falciparuminfecting normal and glucose-6-phosphate dehydrogenase (G6PD)-deficient erythrocytes was assessed by exposure to hydrogen peroxide generated by the glucose–glucose oxidase system. The parasites infecting G6PD-deficient erythrocytes had markedly greater susceptibility to hydrogen peroxide under a variety of conditions than those infecting normal erythrocytes. In both cases, the killing effect was mediated mainly through the host cells since treatment of the erythrocytes with hydrogen peroxide did not change their relative susceptibility. The parasites were most susceptible during maturation, especially in G6PD-deficient erythrocytes, although a reduction in parasite invasion was also observed. The role of oxidant-mediated killing in the protection of G6PD-deficient hosts fromP. falciparuminfection is discussed.

Role of small nuclear RNAs in eukaryotic gene expression

2013 ◽  
Vol 54 ◽  
pp. 79-90 ◽  
Author(s):  
Saba Valadkhan ◽  
Lalith S. Gunawardane
Keyword(s):  
Gene Expression ◽  
Protein Interactions ◽  
Rna Stability ◽  
Splice Sites ◽  
Branch Site ◽  
Small Nuclear Rnas ◽  
Eukaryotic Gene Expression ◽  
Eukaryotic Gene ◽  
Rna Biogenesis

Eukaryotic cells contain small, highly abundant, nuclear-localized non-coding RNAs [snRNAs (small nuclear RNAs)] which play important roles in splicing of introns from primary genomic transcripts. Through a combination of RNA–RNA and RNA–protein interactions, two of the snRNPs, U1 and U2, recognize the splice sites and the branch site of introns. A complex remodelling of RNA–RNA and protein-based interactions follows, resulting in the assembly of catalytically competent spliceosomes, in which the snRNAs and their bound proteins play central roles. This process involves formation of extensive base-pairing interactions between U2 and U6, U6 and the 5′ splice site, and U5 and the exonic sequences immediately adjacent to the 5′ and 3′ splice sites. Thus RNA–RNA interactions involving U2, U5 and U6 help position the reacting groups of the first and second steps of splicing. In addition, U6 is also thought to participate in formation of the spliceosomal active site. Furthermore, emerging evidence suggests additional roles for snRNAs in regulation of various aspects of RNA biogenesis, from transcription to polyadenylation and RNA stability. These snRNP-mediated regulatory roles probably serve to ensure the co-ordination of the different processes involved in biogenesis of RNAs and point to the central importance of snRNAs in eukaryotic gene expression.

The role of copper ions in hydrogen peroxide bleaching: Their origin, removal, and effect on pulp quality

TAPPI Journal ◽  
2012 ◽  
Vol 11 (7) ◽  
pp. 37-46 ◽  
Author(s):  
PEDRO E.G. LOUREIRO ◽  
SANDRINE DUARTE ◽  
DMITRY V. EVTUGUIN ◽  
M. GRAÇA V.S. CARVALHO
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Ions ◽  
Peroxide Bleaching ◽  
Metals Removal ◽  
Peroxide Decomposition ◽  
Equipment Corrosion ◽  
And Performance ◽  
And Control ◽  
Main Effects

This study puts particular emphasis on the role of copper ions in the performance of hydrogen peroxide bleaching (P-stage). Owing to their variable levels across the bleaching line due to washing filtrates, bleaching reagents, and equipment corrosion, these ions can play a major role in hydrogen peroxide decomposition and be detrimental to polysaccharide integrity. In this study, a Cu-contaminated D0(EOP)D1 prebleached pulp was subjected to an acidic washing (A-stage) or chelation (Q-stage) before the alkaline P-stage. The objective was to understand the isolated and combined role of copper ions in peroxide bleaching performance. By applying an experimental design, it was possible to identify the main effects of the pretreatment variables on the extent of metals removal and performance of the P-stage. The acid treatment was unsuccessful in terms of complete copper removal, magnesium preservation, and control of hydrogen peroxide consumption in the following P-stage. Increasing reaction temperature and time of the acidic A-stage improved the brightness stability of the D0(EOP)D1AP bleached pulp. The optimum conditions for chelation pretreatment to maximize the brightness gains obtained in the subsequent P-stage with the lowest peroxide consumption were 0.4% diethylenetriaminepentaacetic acid (DTPA), 80ºC, and 4.5 pH.

An ESR study of the peroxidase reaction catalyzed by human methaemoglobin and methaemoglobin-haptoglobin complex

1991 ◽  
Vol 56 (4) ◽  
pp. 923-932
Author(s):  
Jana Stejskalová ◽  
Pavel Stopka ◽  
Zdeněk Pavlíček
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Amino Acid ◽  
Peroxidase Activity ◽  
Amino Acid Analysis ◽  
Superoxide Radical ◽  
Esr Spectra ◽  
The Other ◽  
Delocalized Electron

The ESR spectra of peroxidase systems of methaemoglobin-ascorbic acid-hydrogen peroxide and methaemoglobin-haptoglobin complex-ascorbic acid-hydrogen peroxide have been measured in the acetate buffer of pH 4.5. For the system with methaemoglobin an asymmetrical signal with g ~ 2 has been observed which is interpreted as the perpendicular region of anisotropic spectrum of superoxide radical. On the other hand, for the system with methaemoglobin-haptoglobin complex the observed signal with g ~ 2 is symmetrical and is interpreted as a signal of delocalized electron. After realization of three repeatedly induced peroxidase processes the ESR signal of the perpendicular part of anisotropic spectrum of superoxide radical is distinctly diminished, whereas the signal of delocalized electron remains practically unchanged. An amino acid analysis of methaemoglobin along with results of the ESR measurements make it possible to derive a hypothesis about the role of haptoglobin in increasing of the peroxidase activity of methaemoglobin.

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