Variation in ascorbic acid oxidation routes in hydrogen peroxide and cupric ion solution as determined by GC/MS

1994 ◽  
Vol 66 (3) ◽  
pp. 345-350 ◽  
Author(s):  
John C. Deutsch ◽  
C. R. Santhosh-Kumar ◽  
Kathryn L. Hassell ◽  
J. Fred. Kolhouse
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Acid Oxidation ◽  
Cupric Ion

scholarly journals THE EFFECT OF ASCORBIC ACID OXIDATION ON THE INCORPORATION OF SULFATE BY SLICES OF CALF COSTAL CARTILAGE

1958 ◽  
Vol 42 (2) ◽  
pp. 303-318 ◽  
Author(s):  
S. J. Klebanoff ◽  
D. D. Dziewiatkowski ◽  
G. J. Okinaka
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Sodium Azide ◽  
Costal Cartilage ◽  
Dehydroascorbic Acid ◽  
Inhibitory Effect ◽  
Considerable Extent ◽  
Acid Oxidation ◽  
Marked Inhibition ◽  
Production Of Hydrogen

A marked inhibition of the incorporation of S35-sulfate by normal calf costal cartilage was produced by potassium ascorbate in the presence of catalytic amounts of cupric ions. The effect of the various components of the ascorbic acid oxidizing system (potassium ascorbate, cupric ions, cuprous ions, hydrogen peroxide, dehydroascorbic acid) was investigated. The results of experiments in which hydrogen peroxide, catalase, or sodium azide were used singly or in combination suggest that the inhibition produced by the ascorbic acid oxidizing system is due, to a considerable extent, to the production of hydrogen peroxide. Dehydroascorbic acid was also found to inhibit the incorporation of S35-sulfate by cartilage slices. However, the gradual fall in pH which resulted from the addition of dehydroascorbic acid could account to a large extent for the inhibitory effect observed because the incorporation of S35-sulfate by cartilage slices decreases sharply as the pH is lowered. The incorporation of S35-sulfate by cartilage slices is inhibited also by increasing the concentration of phosphate.

scholarly journals Oxidation of L-Ascorbic Acid in the Presence of the Copper-Binding Compound from Methanotrophic Bacteria Methylococcus capsulatus (M)

Biomimetics ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 48
Author(s):  
Lidia V. Avdeeva ◽  
Rudolf I. Gvozdev
Keyword(s):  
Hydrogen Peroxide ◽  
Ascorbic Acid ◽  
Rate Constant ◽  
Copper Complex ◽  
Ascorbate Oxidase ◽  
Acid Oxidation ◽  
Copper Binding ◽  
Methylococcus Capsulatus ◽  
Oxidation Stress ◽  
Noncatalytic Reaction

The oxidation of ascorbic acid by air oxygen and hydrogen peroxide in the presence of the copper-binding compound (cbc) from bacteria Methylococcus capsulatus (M) was studied. The rate constant of ascorbic acid oxidation by air oxygen in the presence of the copper complex with cbc from M. capsulatus (M) was shown to be 1.5 times higher than that of the noncatalytic reaction. The rate constant of ascorbic acid oxidation by hydrogen peroxide in the presence of the copper complex with cbc from M. capsulatus (M) decreased by almost one-third compared to the reaction in the absence of the copper complex with cbc. It was assumed that cbc can be involved in a multilevel system of antioxidant protection and can protect a bacterial cell from oxidation stress. Thus, the cbc is mimetic ascorbate oxidase in the oxidation of ascorbic acid by molecular oxygen.

Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method

2019 ◽  
Vol 29 (3) ◽  
Author(s):  
Mai Ngọc Tuan Anh
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Ascorbic Acid ◽  
Silver Nitrate ◽  
Sodium Borohydride ◽  
Trisodium Citrate ◽  
Synthesis And Characterization ◽  
Silver Nanoplates ◽  
Seed Mediated

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag\(^+\) ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods.

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.

Sign in / Sign up

Export Citation Format

Share Document