Phloem Loading of Sucrose: Involvement of Membrane ATPase and Proton Transport 1
AUTOR(ES)
Giaquinta, Robert T.
RESUMO
p-Chloromercuribenzenesulfonic acid markedly inhibited sucrose accumulation into sugar beet source leaves without inhibiting hexose accumulation. The site of inhibition is proposed to be the plasmalemma ATPase, since the ATPase-mediated H+ efflux was completely inhibited by p-chloromercuribenzenesulfonic acid under conditions where intracellular metabolism, as measured by photosynthesis and hexose accumulation, was unaffected. Fusicoccin, a potent activator of active H+/K+ exchange, stimulated both active sucrose accumulation and proton efflux in the sugar beet leaf tissue. These data provide strong evidence for the phloem loading of sucrose being coupled to a proton transport mechanism driven by a vectorial plasmalemma ATPase.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=542909Documentos Relacionados
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