Studies on the proton-translocating NADH:ubiquinone oxidoreductases of mitochondria and Escherichia coli using the inhibitor 1,10-phenanthroline.


Finel, M; Majander, A

Publication Year 1994
Journal FEBS Letters
Pages 142-146
Volume 339
Issue 1-2
PMID 8313963.0
DOI 10.1016/0014-5793(94)80402-8

Mitochondrial NADH:ubiquinone oxidoreductase (complex I) is uncompetitively inhibited by 1,10-phenanthroline (OP). EPR spectroscopy of submitochondrial particles indicates that OP, similarly to rotenone, inhibits electron transfer between the Fe-S clusters of complex I and the ubiquinone pool. The proton-translocating NADH dehydrogenase (NDH1) of E. coli is more sensitive to OP than is NDH1 of Paracoccus. EPR spectroscopy of membranous E. coli NDH1 shows that two slow- and one fast-relaxing Fe-S clusters become detectable upon reduction by NADH in the presence of OP. However, none of them resembles the mitochondrial cluster 2.