Ascorbyl free radical and dehydroascorbate formation in rat liver endoplasmic reticulum
(2002) In Journal of Bioenergetics and Biomembranes 34(4). p.317-323- Abstract
- The mechanism of ascorbate oxidation was studied in rat liver microsomes. A continuous consumption of the added ascorbate was observed, which was accompanied with a prompt appearance of ascorbyl free radical and dehydroascorbate. Microsomes sustained steady-state level of ascorbyl free radical and dehydroascorbate till ascorbate was present in the medium. Ascorbyl free radical formation was diminished when microsomes had been pretreated with heat or trypsine. It was also decreased by addition of quercetin, econazole or metal chelators, including the copper specific neocuproine. Enzymatic (superoxide dismutase, catalase) and nonenzymatic (dimethyl sulfoxide, mannitol) antioxidants did not modify the microsomal production of ascorbyl free... (More)
- The mechanism of ascorbate oxidation was studied in rat liver microsomes. A continuous consumption of the added ascorbate was observed, which was accompanied with a prompt appearance of ascorbyl free radical and dehydroascorbate. Microsomes sustained steady-state level of ascorbyl free radical and dehydroascorbate till ascorbate was present in the medium. Ascorbyl free radical formation was diminished when microsomes had been pretreated with heat or trypsine. It was also decreased by addition of quercetin, econazole or metal chelators, including the copper specific neocuproine. Enzymatic (superoxide dismutase, catalase) and nonenzymatic (dimethyl sulfoxide, mannitol) antioxidants did not modify the microsomal production of ascorbyl free radical. Investigation of the subcellular distribution of ascorbate oxidation showed that the microsomal fraction of liver had the highest activity. The decrease of ascorbate oxidation after protease treatment and the negligible increase upon permeabilization of microsomal vesicles showed that a membrane protein is responsible for the activity, which is exposed to the outer surface of the endoplasmic reticulum. The results indicate the presence of a primary enzymatic ascorbate oxidation in rat liver endoplasmic reticulum which is able to generate dehydroascorbate, an important source of the oxidizing environment in the endoplasmic reticulum. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1124535
- author
- Szarka, Andras ; Stadler, Krisztian ; Jenei, Veronica LU ; Margittai, Eva ; Csala, Miklos ; Jakus, Judit ; Mandl, Jozsef and Banhegyi, Gabor
- publishing date
- 2002
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Bioenergetics and Biomembranes
- volume
- 34
- issue
- 4
- pages
- 317 - 323
- publisher
- Springer
- external identifiers
-
- pmid:12392195
- scopus:0036698219
- ISSN
- 1573-6881
- DOI
- 10.1023/A:1020212720330
- language
- English
- LU publication?
- no
- id
- 56f29f6e-17a2-4707-8336-4587cb4a48cb (old id 1124535)
- date added to LUP
- 2016-04-01 12:00:21
- date last changed
- 2022-01-26 21:28:23
@article{56f29f6e-17a2-4707-8336-4587cb4a48cb,
abstract = {{The mechanism of ascorbate oxidation was studied in rat liver microsomes. A continuous consumption of the added ascorbate was observed, which was accompanied with a prompt appearance of ascorbyl free radical and dehydroascorbate. Microsomes sustained steady-state level of ascorbyl free radical and dehydroascorbate till ascorbate was present in the medium. Ascorbyl free radical formation was diminished when microsomes had been pretreated with heat or trypsine. It was also decreased by addition of quercetin, econazole or metal chelators, including the copper specific neocuproine. Enzymatic (superoxide dismutase, catalase) and nonenzymatic (dimethyl sulfoxide, mannitol) antioxidants did not modify the microsomal production of ascorbyl free radical. Investigation of the subcellular distribution of ascorbate oxidation showed that the microsomal fraction of liver had the highest activity. The decrease of ascorbate oxidation after protease treatment and the negligible increase upon permeabilization of microsomal vesicles showed that a membrane protein is responsible for the activity, which is exposed to the outer surface of the endoplasmic reticulum. The results indicate the presence of a primary enzymatic ascorbate oxidation in rat liver endoplasmic reticulum which is able to generate dehydroascorbate, an important source of the oxidizing environment in the endoplasmic reticulum.}},
author = {{Szarka, Andras and Stadler, Krisztian and Jenei, Veronica and Margittai, Eva and Csala, Miklos and Jakus, Judit and Mandl, Jozsef and Banhegyi, Gabor}},
issn = {{1573-6881}},
language = {{eng}},
number = {{4}},
pages = {{317--323}},
publisher = {{Springer}},
series = {{Journal of Bioenergetics and Biomembranes}},
title = {{Ascorbyl free radical and dehydroascorbate formation in rat liver endoplasmic reticulum}},
url = {{http://dx.doi.org/10.1023/A:1020212720330}},
doi = {{10.1023/A:1020212720330}},
volume = {{34}},
year = {{2002}},
}