Induction by glucose of an antimycin-insensitive, azide-sensitive respiration in the yeast Kluyveromyces lactis.
Increasing the glucose concentration from 0.1 to 10% in exponentially growing cultures of Kluyveromyces lactis CBS 2359 does not repress the antimycin-sensitive respiration (QO2 of 80 microliter O2 . h-1 . mg-1 dry weight) but raises the antimycin-insensitive respiration from 3 to 12 microliter O2 . h-2 . mg-1 dry weight. Antimycin A inhibits the growth of K. lactis on a variety of substrates with the exception of glucose at concentrations equal to or higher than 1% where substantial antimycin-insensitive respiratory rates are induced. It can be concluded that a minimal antimycin-insensitive QO2 is necessary for cellular growth when the normal respiratory pathway is not functional. The antimycin-insensitive respiration elicited by growth in high glucose concentrations is poorly inhibited by hydroxamate and is inhibited by 50% by 90 microM azide or 1 mM cyanide. These concentrations are much higher than those necessary to inhibit cytochrome c oxidase which is not involved in the antimycin-insensitive respiration as was demonstrated by spectral measurements. A pigment absorbing at 555 nm is specifically reduced after addition of glucose to antimycin-inhibited cells. The same pigment is reoxidized by further addition of high concentrations of sodium azide indicating its participation in the antimycin-insensitive, azide-sensitive respiration.
D000968:Antimycin A / Q000494:pharmacology*; D001203:Ascomycota / Q000378:metabolism*; D001386:Azides / Q000494:pharmacology; D050260:Carbohydrate Metabolism; D005656:Fungal Proteins / Q000096:biosynthesis; D005947:Glucose / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*; D004718:Saccharomycetales / Q000254:growth & development / Q000378:metabolism*; D019810:Sodium Azide; D012966:Sodium Cyanide / Q000494:pharmacology
D001386:Azides; D005656:Fungal Proteins; D000968:Antimycin A; D019810:Sodium Azide; D005947:Glucose; D012966:Sodium Cyanide