Characterization of a glutamine/proton cotransporter from Ricinus communis roots using isolated plasma membrane vesicles

1994 ◽  
Vol 91 (4) ◽  
pp. 623-630
Author(s):  
Kim Weston ◽  
J. L. Hall ◽  
Lorraine E. Williams
Keyword(s):  
Plasma Membrane ◽  
Ricinus Communis ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles

scholarly journals Characterization of the plasma-membrane calcium pump from Trypanosoma cruzi

1995 ◽  
Vol 306 (1) ◽  
pp. 299-303 ◽  
Author(s):  
G Benaim ◽  
S N J Moreno ◽  
G Hutchinson ◽  
V Cervino ◽  
T Hermoso ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Trypanosoma Cruzi ◽  
Mammalian Cells ◽  
Membrane Vesicles ◽  
High Sensitivity ◽  
Bovine Brain ◽  
Calcium Pump ◽  
Plasma Membrane Vesicles ◽  
P Type

Despite previous reports [McLaughlin (1985) Mol. Biochem. Parasitol. 15, 189-201; Ghosh, Ray, Sarkar and Bhaduri (1990) J. Biol. Chem. 265, 11345-11351; Mazumder, Mukherjee, Ghosh, Ray and Bhaduri (1992) J. Biol. Chem. 267, 18440-18446] suggesting that the plasma-membrane Ca(2+)-ATPases of different trypanosomatids differ from the Ca2+ pumps present in mammalian cells, Trypanosoma cruzi plasma-membrane Ca(2+)-ATPase shares several characteristics with the Ca2+ pumps present in other systems. This enzyme could be partially purified from epimastigote plasma-membrane vesicles using calmodulin-agarose affinity chromatography. The activity of the partially purified enzyme was stimulated by T. cruzi or bovine brain calmodulin. In addition, the enzyme cross-reacted with antiserum and monoclonal antibody 5F10 raised against human red-blood-cell Ca(2+)-ATPase, has a molecular mass of 140 kDa and forms Ca(2+)-dependent hydroxylamine-sensitive phosphorylated intermediates. These results, together with its high sensitivity to vanadate, indicate that this enzyme belongs to the P-type class of ionic pumps.

Synthesis of NTA3-DTDA — A Chelator-Lipid that Promotes Stable Binding of His-Tagged Proteins to Membranes

2006 ◽  
Vol 59 (5) ◽  
pp. 302 ◽  
Author(s):  
Joseph G. Altin ◽  
Martin G. Banwell ◽  
Phillip A. Coghlan ◽  
Christopher J. Easton ◽  
Michael R. Nairn ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Targeted Delivery ◽  
Membrane Vesicles ◽  
Spectroscopic Characterization ◽  
Plasma Membrane Vesicles ◽  
Reaction Sequence ◽  
Type Compound

A six-step reaction sequence is described for the preparation of compound 1 (NTA3-DTDA), a membrane-penetrating and potent chelator that can be incorporated into liposomes and plasma membrane vesicles containing antigens and thus allowing targeted delivery of such assemblies to a variety of cells for the purposes of eliciting anti-tumour responses. Full spectroscopic characterization of this dendritic-type compound as well as certain of its precursors is reported.

scholarly journals Characterization of Ca2+ fluxes in rat liver plasma-membrane vesicles

1988 ◽  
Vol 256 (1) ◽  
pp. 117-124 ◽  
Author(s):  
C Dargemont ◽  
M Hilly ◽  
M Claret ◽  
J P Mauger
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Uptake Rate ◽  
Ionic Composition ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Microsomal Preparation ◽  
Intact Cells ◽  
Inside Out

Inside-out plasma-membrane vesicles isolated from rat liver [Prpic, Green, Blackmore & Exton (1984) J. Biol. Chem. 259, 1382-1385] accumulated a substantial amount of 45Ca2+ when they were incubated in a medium whose ionic composition and pH mimicked those of cytosol and which contained MgATP. The Vmax of the initial 45Ca2+ uptake rate was 2.9 +/- 0.6 nmol/min per mg and the Km for Ca2+ was 0.50 +/- 0.08 microM. The ATP-dependent 45Ca2+ uptake by inside-out plasma-membrane vesicles was about 20 times more sensitive to saponin than was the ATP-dependent uptake by a microsomal preparation. The 45Ca2+ efflux from the inside-out vesicles, which is equivalent to the Ca2+ influx in intact cells, was increased when the free Ca2+ concentration in the medium was decreased. The Ca2+ antagonists La3+ and Co2+ inhibited the 45Ca2+ efflux from the vesicles. Neomycin stimulated the Ca2+ efflux in the presence of either a high or a low free Ca2+ concentration. These results confirm that polyvalent cations regulate Ca2+ fluxes through the plasma membrane.

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