title: Inhibition of cytochrome c oxidase by psychosine (galactosylsphingosine).
abstract: Pi uptake and acetoacetate formation were suppressed by psychosine (galactosylsphingosine) in rat liver mitochondria. Besides, reduced form of cytochrome c increased in the reaction mixture which contained psychosine. Using reduced form of cytochrome c as substrate, less than 5 microM of psychosine (0.1 mumoles/mg of mitochondrial protein) inhibited cytochrome c oxidase by more than 50%. The inhibition was completely reversed by 1% human serum albumin. Thus, a lipid which is produced in the brain has a powerful and yet reversible inhibitory effect on an enzyme of cellular respiration.
mesh_terms: D000090:Acetoacetates / Q000378:metabolism; D000818:Animals; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors*; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D011609:Psychosine / Q000494:pharmacology*; D051381:Rats; D013110:Sphingosine / Q000031:analogs & derivatives*
chemical_list: D000090:Acetoacetates; D010710:Phosphates; D011609:Psychosine; C016635:acetoacetic acid; D003576:Electron Transport Complex IV; D013110:Sphingosine