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Quantitative Autoradiography of Dihydrorotenone Binding to Complex I of the Electron Transport Chain
Author(s) -
Greenamyre J. Timothy,
Higgins Donald S.,
Eller Robert V.
Publication year - 1992
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1992.tb09431.x
Subject(s) - electron transport chain , chemistry , chain (unit) , biophysics , biochemistry , physics , biology , quantum mechanics
Defective complex I activity has been linked to Parkinson's disease and Huntington's disease, but little is known of the regional distribution of this enzyme in the brain. We have developed a quantitative autoradiographic assay using [ 3 H]dihydrorotenone ([ 3 H]DHR) to label and localize complex I in brain tissue sections. Binding was specific and saturable and in the cerebellar molecular layer had a K D of 11.5 ± 1.3 n M and a B max of 11.0 ± 0.4 nCi/mg of tissue. Unlabeled rotenone and 1‐methyl‐4‐phenylpyridinium ion competed effectively for DHR binding sites. Binding was markedly enhanced by 100 μM NADH. The distribution of complex 1 in brain, as revealed by DHR autoradiography, is unique but somewhat similar to that of cytochrome oxidase (complex IV). This assay may provide new insight into the roles of complex I in brain function and neurodegeneration.