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Thermolability of the Alternative Electron Transport Pathway in Higher Plant Mitochondria
Author(s) -
CHAUVEAU M.,
DIZENGREMEL P.,
LANCE C.
Publication year - 1978
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1978.tb02550.x
Subject(s) - cyanide , alternative complement pathway , mitochondrion , electron transport chain , alternative oxidase , biochemistry , cytochrome c , hydrogen sulfide , chemistry , cytochrome , biology , hydrogen cyanide , sulfide , enzyme , sulfur , organic chemistry , complement system , antibody , immunology
Mitochondria from four plant species showing normal ( Arum maculatum L., Arum italicum Mill., Sauromatum guttatum Schott) or induced ( Solanum tuberosum L.) resistance to cyanide were submitted to temperature treatments up to 90 min at 45°C. The activity of the alternative, cyanide‐resistant electron transport pathway was specifically and deeply altered by temperature treatments. Hydrogen sulfide was released in direct proportion to the reduction of activity of the alternative pathway. Only a small fraction (≃ 20%) of the total labile sulfide content of the mitochondria was associated with the operation of this pathway. In cyanide‐resistant mitochondria, the cytochrome pathway was much more resistant to thermal inactivation than the alternative pathway. On the contrary, in cyanide‐sensitive mitochondria (with no alternative pathway) the cytochrome pathway was highly sensitive to temperature treatments. These results indicate that the presence of a cyanide‐resistant alternative pathway is correlated with a higher degree of resistance to thermal denaturation of the cytochrome pathway. They also strongly suggest that iron‐sulfur proteins are regular components of the alternative pathway.