The distribution of electron flow in the branched respiratory chain of Micrococcus luteus.
Endogenous coupled respiration of Micrococcus luteus protoplasts showed a relatively high resistance to low concentrations of KCN, 2-nonyl-4-hydroxyquinoline N-oxide (NQNO) and dicyclohexylcarbodi-imide (DCCD) when the inhibitors were applied individually. In the presence of both KCN and NQNO (or DCCD), O2 uptake was strongly inhibited. The proteolysis of external membrane proteins of protoplasts also induced the high sensitivity of endogenous coupled respiration to low KCN. The effects of NQNO, DCCD and proteolysis were explained by the inhibition of an alternative respiratory system when reducing equivalents passed preferentially down the KCN-sensitive cytochrome oxidase. Uncoupling of the cell membrane increased the electron flow via the cytochrome oxidase-containing respiratory branch. It is suggested that the energy state of cells could control the electron-flow distribution between two branches, and quinones of different levels of reduction could be involved in the mechanism of respiratory branching.
Artzatbanov VYu
A. N. Bach Institute of Biochemistry, U.S.S.R. Academy of Sciences, Moscow.
Ostrovsky
D N
DN
D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002462:Cell Membrane / Q000502:physiology / Q000648:ultrastructure; D004024:Dicyclohexylcarbodiimide / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D003576:Electron Transport Complex IV / Q000378:metabolism; D004734:Energy Metabolism / Q000187:drug effects; D006912:Hydroxyquinolines / Q000494:pharmacology; D066298:In Vitro Techniques; D008837:Micrococcus / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D010447:Peptide Hydrolases / Q000494:pharmacology; D011190:Potassium Cyanide / Q000494:pharmacology
D006912:Hydroxyquinolines; C010494:nonyl-4-hydroxyquinoline-N-oxide; D004024:Dicyclohexylcarbodiimide; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D003576:Electron Transport Complex IV; D010447:Peptide Hydrolases; D011190:Potassium Cyanide