Investigation of the effects of Zn2+ and Cu2+ on the K+ transport in yeast mitochondria. Evidences for the involvement of a Zn(2+)-binding protein in the K+/H+ exchange.
Effect of Zn2+ and Cu2+ were studied on the spontaneous swelling of yeast mitochondria in potassium acetate. (i) Whatever the pH, Cu2+ stimulated the swelling. (ii) Zn2+ inhibited or stimulated the swelling depending both on pH of the medium and of its concentration: it induced an inhibition of the K+/H+ exchange at pH 6.8 and a stimulation at pH 7.7; at pH 7.4, Zn2+ inhibited the swelling at low concentration and stimulated the swelling at higher concentration. (iii) The thiol reagent mersalyl prevented the inhibition by Zn2+ whereas N-ethylmaleimide and 5,5'-dithiobis(2-nitrobenzoate) prevented the stimulation by Zn2+: this allowed to hypothesize that two distinct Zn(2+)-binding sites were involved in the inhibition and in the stimulation of the swelling of yeast mitochondria suspended in potassium acetate.
Manon
S
S
Institut de Biochemie et de Génétique Cellulaires du Centre National de la Recherche Scientifique, Université de Bordeaux II, France.
Guérin
M
M
D017920:Antiporters / Q000378:metabolism; D001665:Binding Sites; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000378:metabolism*; D002413:Cations, Divalent; D003300:Copper / Q000494:pharmacology*; D004228:Dithionitrobenzoic Acid / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008634:Mersalyl / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D008933:Mitochondrial Swelling / Q000187:drug effects; D011188:Potassium / Q000378:metabolism*; D027961:Potassium-Hydrogen Antiporters; D012441:Saccharomyces cerevisiae / Q000648:ultrastructure*; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology*
D017920:Antiporters; D002352:Carrier Proteins; D002413:Cations, Divalent; D027961:Potassium-Hydrogen Antiporters; D013438:Sulfhydryl Compounds; C017800:zinc-binding protein; D008634:Mersalyl; D003300:Copper; D004228:Dithionitrobenzoic Acid; D015032:Zinc; D005033:Ethylmaleimide; D011188:Potassium