Interactions of arsenate, sulfate and phosphate with yeast mitochondria

Citation
P. Cortes et al., Interactions of arsenate, sulfate and phosphate with yeast mitochondria, BBA-BIOENER, 1456(2-3), 2000, pp. 67-76
Citations number
40
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS
ISSN journal
0005-2728 → ACNP
Volume
1456
Issue
2-3
Year of publication
2000
Pages
67 - 76
Database
ISI
SICI code
0005-2728(20000110)1456:2-3<67:IOASAP>2.0.ZU;2-P
Abstract
In the presence of K+, addition of ATP or ethanol to yeast mitochondria tri ggers the depletion of the transmembrane potential (Delta Psi) and this is prevented by millimolar concentrations of phosphate (PO4). Different monova lent and polyvalent anions were tested for their protective effects on mito chondria from Saccharomyces cerevisiae. Only arsenate (AsO4) and sulfate (S O4) were as efficient as PO4 to protect mitochondria against the K+ mediate d swelling, depletion of the Delta Psi, and decrease in the ratio of uncoup led state to state 4 respiration rates. Protection by PO4, SO4 or AsO4 was inhibited by mersalyl, suggesting that these anions interact with a site lo cated in the matrix side. In addition, the effects of SO4 and AsO4 on the F 1F0-ATPase were tested: both SO4 and AsO4 inhibited the synthesis of ATP fo llowing competitive kinetics against PO4 and non-competitive kinetics again st ADP. The mersalyl sensitive uptake of (PO4)-P-32 was not inhibited by SO 4 or AsO4, suggesting that the synthesis of ATP was inhibited at the F1F0-A TPase. The hydrolysis of ATP was not inhibited, only a stimulation was obse rved when AsO4 or sulfite (SO3) were added. It is suggested that the struct ure and charge similarities of PO4, AsO4 and SO4 result in undiscriminated binding to at least two sites located in the mitochondrial matrix: at one s ite, occupation by any of these three anions results in protection against uncoupling by K+; at the second site, in the F1F0-ATPase, AsO4 and SO4 comp ete for binding against PO4 leading to inhibition of the synthesis of ATP. (C) 2000 Elsevier Science B.V. All rights reserved.