ISSN:
1432-2048
Keywords:
V-ATPase-immunocytochemistry
;
Pea cotyledon
;
Plasma membrane
;
Putative γ-TIP
;
Pyrophosphatase
;
Tonoplast markers
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The tonoplast is usually characterized by the presence of two electrogenic proton pumps: a vacuolartype H+-ATPase and a pyrophosphatase, as well as a putative water-channel-forming protein (γ-TIP). Using a post-embedding immunogold labelling technique, we have detected the presence of these transport-protein complexes not only in the tonoplast, but also in the plasma membrane and trans Golgi elements of maturing pea (Pisum sativum L.) cotyledons. These ultrastructural observations are supported by Western blotting with highly purified plasma-membrane fractions. In contrast to the vacuolar-type H+-ATPase, whose activity was not measurable, considerable pyrophosphatase activity was detected in the plasma-membrane fraction. These results are discussed in terms of a possible temporary repository for tonoplast proteins en route to the vacuole.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00197591
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