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Calcium uptake by tonoplast and plasma membrane vesicles from spinach leaves
Author(s) -
Malatialy L.,
Greppin H.,
Penel C.
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)81383-8
Subject(s) - protonophore , chemistry , vanadate , vesicle , vacuole , spinach , calcium , calmodulin , verapamil , biochemistry , membrane , biophysics , chromatography , biology , cytoplasm , enzyme , organic chemistry
Tonoplast‐ and plasma membrane‐enriched fractions were simultaneously prepared from the same crude membrane suspension from spinach leaves by free‐flow electrophoresis. They were used for in vitro ATP‐dependent Ca 2+ ‐uptake studies. The plasma membrane‐enriched fraction accumulated Ca 2+ at a rather slow rate by a mechanism which was inhibited by orthovanadate, insensitive to nitrate and activated by calmodulin. The tonoplast‐enriched fraction accumulated Ca 2+ at a high rate for 5 min, then the accumulated Ca 2+ progressively leaked out of the vesicles. The tonoplast transport system was partly inhibited by nitrate, but also by vanadate, completely abolished by the protonophore CCCP and activated by calmodulin and the Ca 2+ antagonist verapamil.