Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/99618
Type: Artigo de periódico
Title: Calcium Transport By Corn Mitochondria: Evaluation Of The Role Of Phosphate
Author: Silva M.A.P.
Carnieri E.G.S.
Vercesi A.E.
Abstract: Mitochondria from some plant tissues possess the ability to take up Ca2+ by a phosphate-dependent mechanism associated with a decrease in membrane potential, H+ extrusion, and increase in the rate of respiration (AE Vercesi, L Pereira da Silva, IS Martins, CF Bernardes, EGS Carnieri, MM Fagian [1989] In G Fiskum, ed, Cell Calcium Metabolism. Plenum Press, New York, pp 103-111). The present study reexamined the nature of the phosphate requirement in this process. The main observations are: (a) Respiration-coupled Ca2+ uptake by isolated corn (Zea mays var Maya Normal) mitochondria or carbonyl cyanide p-trifluoromethoxyphenylhydrazone-induced efflux of the cation from such mitochondria are sensitive to mersalyl and cannot be dissociated from the silmultaneous movement of phosphate in the same direction, (b) Ruthenium red-induced efflux is not affected by mersalyl and can occur in the absence of phosphate movement. (c) In Ca2+-loaded corn mitochondria, mersalyl causes net Ca2+ release unrelated to a decrease in membrane potential, probably due to an inhibition of Ca2+ cycling at the level of the influx pathway. It is concluded that corn mitochondria (and probably other plant mitochondria) do possess an electrophoretic influx pathway that appears to be a mersalyl-sensitive Ca2+/inorganic phosphate-symporter and a phosphate-independent efflux pathway possibly similar to the Na2+-independent Ca2+ efflux mechanism of vertebrate mitochondria, because it is not stimulated by Na+.
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Address: http://www.scopus.com/inward/record.url?eid=2-s2.0-0001064932&partnerID=40&md5=c907c0a9d7eecf4a47ec97bb28e079cf
Date Issue: 1992
Appears in Collections:Unicamp - Artigos e Outros Documentos

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