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Artigo Produção Nacional Revisado por pares
BIBTEX RIS

A new model for proton pumping in animal cells: the role of pyrophosphate

2003; Elsevier BV; Volume: 34; Issue: 1 Linguagem: Inglês

10.1016/j.ibmb.2003.07.002

ISSN

1879-0240

Autores

Lucimar S. Motta, Wagner Seixas da‐Silva, Danielle Maria Perpétua de Oliveira, Wanderley de Souza, Ednildo A. Machado,

Tópico(s)

Electron Spin Resonance Studies

Resumo

The H+-PPase activity was characterized in membrane fractions of ovary and eggs of Rhodnius prolixus. This activity is totally dependent on Mg2+, independent of K+ and strongly inhibited by NaF, IDP and Ca2+. The membrane proteins of eggs were analyzed by western blot using antibodies to the H+-PPase from Arabidopsis thaliana. The immunostain was associated with a single 65-kDa polypeptide. This polypeptide was immunolocalized in yolk granule membranes by optical and transmission electron microscopy. We describe the acidification of yolk granules in the presence of PPi and ATP. This acidification is inhibited in the presence of NAF, Ca2+ and antibodies against H+-PPase. These data show for the first time in animal cells that acidification of yolk granules involves an H+-PPase as well an H+-ATPase.

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