Stoner and Hanson - Swelling in Corn Atitochondria
نویسندگان
چکیده
Sunhinary. A survey has been ii)ade of the p)rol)erties of cori wlitoc(hon(rlia in .swelling and contraction. The mitochoni(lria swell spontalneouisly in KCl but not in sucrose. Aged mitochondria will swell rapidly in sucrose if treate(l Nvith citrate or ED'FA. Swelling does not impair oxidative phosphorylation if bovine ser-niiii albumin is p)resellt. Contraction can be maintained or initiated with ATP XMg or anl oxi(lizable substrate, contraction being imore rapid with the subst,rate. Alagnesiuni is n1ot re(uire(l for substrate powered contraction. Contraction powered by ATP is accompanied by tlle release of phosphate. Oligonmycin inhibits both ATP-powered contractioni and the release of phosphate. However, it does not affect substrate-powere(l contraction. SuEbstrate powered contraction is inhibited by electron-tranlsport inhibitors. T'hle unlcoupler. carbonyl cyanide m-chlorophenyl hydrazone, accelerates swelling and(I inhibits both AT1P and substrate-powNiered contraction. However, the concentratioi's require(d are well in excess of those required to produce uncoupling and to accelerate adeniosine triphosphatase; the concenitrationis required inhibit respiration in a phosphorylatig,meditui. Phosphate is a very effective inhibitor of succinate-powered contraction. Neither oligomycini nor Mfg affects the lphosphate inhibition. Phosphate is less inhibitory \ith tlle ATP-powered contraction. 'rhe results are (liscussed in termiis of a hypothesis that conitractioni is associate( \\ ith a nonphosphorylate(l higlh energy intermediate of oxi(dati\e pllosph) or1rlatioll.
منابع مشابه
Activation of endogenous respiration and anion transport in corn mitochondria by acidification of the medium.
Acidification of the suspending medium of corn mitochondria (Zea mays L., WF9 x Mo17) from pH 7.5 to pH 6.8 to 6.4 initiates osmotic swelling with the transportable anions citrate, sulfate, and phosphate. Swelling becomes pronounced with a combination of citrate plus sulfate or phosphate. Acidification proves to activate endogenous respiration, which is essentially zero at pH 7.5. The endogenou...
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