Linked Life Data

12171070

Source:http://linkedlifedata.com/resource/pubmed/id/12171070

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2002-8-12
pubmed:abstractText
We have studied changes in plasma membrane NAD(P)H:quinone oxidoreductases of HL-60 cells under serum withdrawal conditions, as a model to analyze cell responses to oxidative stress. Highly enriched plasma membrane fractions were obtained from cell homogenates. A major part of NADH-quinone oxidoreductase in the plasma membrane was insensitive to micromolar concentrations of dicumarol, a specific inhibitor of the NAD(P)H:quinone oxidoreductase 1 (NQOI, DT-diaphorase), and only a minor portion was characterized as DT-diaphorase. An enzyme with properties of a cytochrome b5 reductase accounted for most dicumarol-resistant quinone reductase activity in HL-60 plasma membranes. The enzyme used mainly NADH as donor, it reduced coenzyme Q0 through a one-electron mechanism with generation of superoxide, and its inhibition profile by p-hydroxymercuribenzoate was similar to that of authentic cytochrome b5 reductase. Both NQO1 and a novel dicumarol-insensitive quinone reductase that was not accounted by a cytochrome b5 reductase were significantly increased in plasma membranes after serum deprivation, showing a peak at 32 h of treatment. The reductase was specific for NADH, did not generate superoxide during quinone reduction, and was significantly resistant to p-hydroxymercuribenzoate. The function of this novel quinone reductase remains to be elucidated whereas dicumarol inhibition of NQO1 strongly potentiated growth arrest and decreased viability of HL-60 cells in the absence of serum. Our results demonstrate that upregulation of two-electron quinone reductases at the plasma membrane is a mechanism evoked by cells for defense against oxidative stress caused by serum withdrawal.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0145-479X
pubmed:author
pubmed:issnType
Print
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
209-19
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
A novel plasma membrane quinone reductase and NAD(P)H:quinone oxidoreductase 1 are upregulated by serum withdrawal in human promyelocytic HL-60 cells.
pubmed:affiliation
Departamento de Biología Celular, Fisiología e Immunología, Facultad de Ciencias, Universidad de Córdoba, Spain.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't