Abstract
The cleavage of tert-butyl hydroperoxide by submitochondrial particles yielded two distinctive radicals, alkoxyl and methyl radicals, detected by the electron paramagnetic resonance technique in conjunction with the spin trap 5-5′-dimethyl-1-pyrrolyne-N-oxide. Free radical formation was partly sensitive to bathocuproine disulfonate and was augmented upon supplementation of the mitochondrial membranes with copper, thus suggesting that a redox active copper pool in mitochondrial membranes participated actively in the cleavage of the OO bond of tert-butyl hydroperoxide. This view was experimentally substantiated by teh following: first, observation of the maximal EPR signal intensity required the presence of exogenous electron donors, such as succinate or reduced nicotinamide adenine dinucleotide (NADH). Second, copper reduction was accomplished partly by a superoxide radical-dependent mechanism as indicated by the sensitivity of the electron paramagnetic resonance (EPR) signal to superoxide dismutase. Third, the enhancing effec of the respiratory chain inhibitors, antimycin A and rotenone, on free radical yield assessed in the presence of superoxide dismutase pointed to the occurrence of two potential loci in the respiratory chain involved in direct electron transfer to membrane-bound copper: one located between NADH and the rotenone-sensitive site and another, quantitatively less important, between the rotenone- and antimycin-sensitive sites. These results support the notion that a redox pool of cooper tightly bound to the mitochondrial membrane contributes significantly to the reductive cleavage of organic peroxides associated with free radical production.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 559-565 |
| Number of pages | 7 |
| Journal | Free Radical Biology and Medicine |
| Volume | 14 |
| Issue number | 5 |
| DOIs | |
| State | Published - 1993 |
| Externally published | Yes |
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Keywords
- Alkoxyl radical
- Copper
- Electron transport
- EPR
- Free radicals
- Hydroperoxide
- Spin trapping
- Submitochondrial particles
ASJC Scopus subject areas
- Clinical Biochemistry
- Medicine(all)
- Toxicology
Cite this
Alkoxyl and methyl radical formation during cleavage of tert-butyl hydroperoxide by a mitochondrial membrane-bound, redox active copper pool : An EPR study. / Massa, Eddy M.; Giulivi, Cecilia R.
In: Free Radical Biology and Medicine, Vol. 14, No. 5, 1993, p. 559-565.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Alkoxyl and methyl radical formation during cleavage of tert-butyl hydroperoxide by a mitochondrial membrane-bound, redox active copper pool
T2 - An EPR study
AU - Massa, Eddy M.
AU - Giulivi, Cecilia R
PY - 1993
Y1 - 1993
N2 - The cleavage of tert-butyl hydroperoxide by submitochondrial particles yielded two distinctive radicals, alkoxyl and methyl radicals, detected by the electron paramagnetic resonance technique in conjunction with the spin trap 5-5′-dimethyl-1-pyrrolyne-N-oxide. Free radical formation was partly sensitive to bathocuproine disulfonate and was augmented upon supplementation of the mitochondrial membranes with copper, thus suggesting that a redox active copper pool in mitochondrial membranes participated actively in the cleavage of the OO bond of tert-butyl hydroperoxide. This view was experimentally substantiated by teh following: first, observation of the maximal EPR signal intensity required the presence of exogenous electron donors, such as succinate or reduced nicotinamide adenine dinucleotide (NADH). Second, copper reduction was accomplished partly by a superoxide radical-dependent mechanism as indicated by the sensitivity of the electron paramagnetic resonance (EPR) signal to superoxide dismutase. Third, the enhancing effec of the respiratory chain inhibitors, antimycin A and rotenone, on free radical yield assessed in the presence of superoxide dismutase pointed to the occurrence of two potential loci in the respiratory chain involved in direct electron transfer to membrane-bound copper: one located between NADH and the rotenone-sensitive site and another, quantitatively less important, between the rotenone- and antimycin-sensitive sites. These results support the notion that a redox pool of cooper tightly bound to the mitochondrial membrane contributes significantly to the reductive cleavage of organic peroxides associated with free radical production.
AB - The cleavage of tert-butyl hydroperoxide by submitochondrial particles yielded two distinctive radicals, alkoxyl and methyl radicals, detected by the electron paramagnetic resonance technique in conjunction with the spin trap 5-5′-dimethyl-1-pyrrolyne-N-oxide. Free radical formation was partly sensitive to bathocuproine disulfonate and was augmented upon supplementation of the mitochondrial membranes with copper, thus suggesting that a redox active copper pool in mitochondrial membranes participated actively in the cleavage of the OO bond of tert-butyl hydroperoxide. This view was experimentally substantiated by teh following: first, observation of the maximal EPR signal intensity required the presence of exogenous electron donors, such as succinate or reduced nicotinamide adenine dinucleotide (NADH). Second, copper reduction was accomplished partly by a superoxide radical-dependent mechanism as indicated by the sensitivity of the electron paramagnetic resonance (EPR) signal to superoxide dismutase. Third, the enhancing effec of the respiratory chain inhibitors, antimycin A and rotenone, on free radical yield assessed in the presence of superoxide dismutase pointed to the occurrence of two potential loci in the respiratory chain involved in direct electron transfer to membrane-bound copper: one located between NADH and the rotenone-sensitive site and another, quantitatively less important, between the rotenone- and antimycin-sensitive sites. These results support the notion that a redox pool of cooper tightly bound to the mitochondrial membrane contributes significantly to the reductive cleavage of organic peroxides associated with free radical production.
KW - Alkoxyl radical
KW - Copper
KW - Electron transport
KW - EPR
KW - Free radicals
KW - Hydroperoxide
KW - Spin trapping
KW - Submitochondrial particles
UR - http://www.scopus.com/inward/record.url?scp=0027221717&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027221717&partnerID=8YFLogxK
U2 - 10.1016/0891-5849(93)90114-A
DO - 10.1016/0891-5849(93)90114-A
M3 - Article
C2 - 8394271
AN - SCOPUS:0027221717
VL - 14
SP - 559
EP - 565
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
SN - 0891-5849
IS - 5
ER -