Linked Life Data

9542060

Source:http://linkedlifedata.com/resource/pubmed/id/9542060

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1998-5-1
pubmed:abstractText
The mechanism of ascorbate oxidation by metal-binding proteins (ceruloplasmin, albumin and transferrin) was investigated in vitro and in isolated plasma by the measurement of the ascorbyl free radicals (AFR) by electron spin resonance (ESR). In plasma of 13 healthy volunteers, a spontaneous and variable production of AFR was detected, which was increased by a 10(-4) M ascorbate overloading; however, this increase was not correlated to the intensity of the spontaneous AFR signal. The addition of Cu2+ and ceruloplasmin to plasma increased the ESR signal, while the addition of transferrin decreased the signal intensity in a dose-dependent manner. In vitro, we demonstrated that ascorbate was oxidized by human serum albumin and by ceruloplasmin, and that this oxidase-like activity was lost by trypsin or heat treatment of these proteins. These two proteins positively interacted in the oxidation of ascorbate, since addition of crude albumin to a solution of ascorbate and ceruloplasmin increased the intensity of ESR signal in a dose-dependent manner. The treatment of albumin by a metal chelator (DDTC) abolished these positive interactions. The respective roles of copper and iron in ascorbate oxidation were studied and showed a dose-dependent effect of these ions on ascorbate oxidation. The role of iron was confirmed by the inhibiting effect of metal-free transferrin on iron-dependent ascorbate oxidation. Concerted actions between iron carrying albumin and copper carrying ceruloplasmin appear responsible for the production of AFR in vitro and in vivo.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Anticoagulants, http://linkedlifedata.com/resource/pubmed/chemical/Ascorbate Oxidase, http://linkedlifedata.com/resource/pubmed/chemical/Ceruloplasmin, http://linkedlifedata.com/resource/pubmed/chemical/Chelating Agents, http://linkedlifedata.com/resource/pubmed/chemical/Copper, http://linkedlifedata.com/resource/pubmed/chemical/Dehydroascorbic Acid, http://linkedlifedata.com/resource/pubmed/chemical/Ditiocarb, http://linkedlifedata.com/resource/pubmed/chemical/Free Radicals, http://linkedlifedata.com/resource/pubmed/chemical/Iron, http://linkedlifedata.com/resource/pubmed/chemical/Metals, http://linkedlifedata.com/resource/pubmed/chemical/Serum Albumin, http://linkedlifedata.com/resource/pubmed/chemical/Transferrin, http://linkedlifedata.com/resource/pubmed/chemical/semidehydroascorbic acid
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0966-0844
pubmed:author
pubmed:issnType
Print
pubmed:volume
11
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
81-8
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
An electron spin resonance (ESR) study on the mechanism of ascorbyl radical production by metal-binding proteins.
pubmed:affiliation
Centre for the Biochemistry of Oxygen, Université de Liège, Domaine Universitaire du Sart Tilman, Belgium. gdeby@ulg.ac.be
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't