scholarly journals Modulation of H+-ATPase Activity by Fusicoccin in Plasma Membrane Vesicles from Oat (Avena sativa L.) Roots (A Comparison of Modulation by Fusicoccin, Trypsin, and Lysophosphatidylcholine)

1994 ◽  
Vol 104 (4) ◽  
pp. 1277-1285 ◽  
Author(s):  
F. C. Lanfermeijer ◽  
HBA. Prins
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Avena Sativa ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles

Effect of antimicrobial peptides on ATPase activity and proton pumping in plasma membrane vesicles obtained from mycobacteria

Peptides ◽  
2012 ◽  
Vol 36 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Paola Santos ◽  
Aldemar Gordillo ◽  
Luis Osses ◽  
Luz-Mary Salazar ◽  
Carlos-Yesid Soto
Keyword(s):  
Plasma Membrane ◽  
Antimicrobial Peptides ◽  
Atpase Activity ◽  
Membrane Vesicles ◽  
Proton Pumping ◽  
Plasma Membrane Vesicles

scholarly journals Characteristics of the Ca2+ pump and Ca2+-ATPase in the plasma membrane of rat myometrium

1988 ◽  
Vol 252 (1) ◽  
pp. 215-220 ◽  
Author(s):  
A Enyedi ◽  
J Minami ◽  
A J Caride ◽  
J T Penniston
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Calcium Uptake ◽  
Limited Proteolysis ◽  
Membrane Vesicles ◽  
Calcium Pump ◽  
Ionophore A23187 ◽  
Plasma Membrane Vesicles ◽  
Active Calcium ◽  
Stimulation Of

A plasma membrane-enriched fraction from rat myometrium shows ATP-Mg2+-dependent active calcium uptake which is independent of the presence of oxalate and is abolished by the Ca2+ ionophore A23187. Ca2+ loaded into vesicles via the ATP-dependent Ca2+ uptake was released by extravesicular Na+. This showed that the Na+/Ca2+ exchange and the Ca2+ uptake were both occurring in plasma membrane vesicles. In a medium containing KCl, vanadate readily inhibited the Ca2+ uptake (K1/2 5 microM); when sucrose replaced KCl, 400 microM-vanadate was required for half inhibition. Only a slight stimulation of the calcium pump by calmodulin was observed in untreated membrane vesicles. Extraction of endogenous calmodulin from the membranes by EGTA decreased the activity and Ca2+ affinity of the calcium pump; both activity and affinity were fully restored by adding back calmodulin or by limited proteolysis. A monoclonal antibody (JA3) directed against the human erythrocyte Ca2+ pump reacted with the 140 kDa Ca2+-pump protein of the myometrial plasma membrane. The Ca2+-ATPase activity of these membranes is not specific for ATP, and is not inhibited by mercurial agents, whereas Ca2+ uptake has the opposite properties. Ca2+-ATPase activity is also over 100 times that of calcium transport; it appears that the ATPase responsible for transport is largely masked by the presence of another Ca2+-ATPase of unknown function. Measurements of total Ca2+-ATPase activity are, therefore, probably not directly relevant to the question of intracellular Ca2+ control.

scholarly journals 131 PEROXIDATIVE CHALLENGE OF PLASMA MEMBRANE VESICLES FROM BELL PEPPER FRUIT LEADS TO DECREASED H+ATPase ACTIVITY

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 447c-447
Author(s):  
Darlene M. Cowart ◽  
Robert L. Shewfelt
Keyword(s):  
Plasma Membrane ◽  
Atpase Activity ◽  
Fruits And Vegetables ◽  
Chilling Injury ◽  
Membrane Vesicles ◽  
Thiobarbituric Acid ◽  
Plasma Membrane Vesicles ◽  
Water Control ◽  
Solubilized Enzyme

-Lipid peroxidation has been proposed as an important factor in chilling injury of susceptible fruits and vegetables. The effect of in vitro peroxidative challenge on H+ATPase activity in intact plasma membrane vesicles and solubilized enzyme was determined by incubation with (1) deionized water (control), (2) Fe3+-ascorbate, and (3) lipoxygenase (LOX) + phospholipase A2(PLA2) for 0, 30, and 60 min. Enzyme activity increased throughout the incubation period with no accumulation of thiobarbituric acid-reactive substances (TBA-RS) in the control, but vesicles challenged by the peroxidative systems showed significant increases in TBA-RS and decreases in membrane-bound H+ATPase activity. Greater losses in H+ATPase activity were observed in solubilized enzyme than in intact vesicles. The results indicate that loss of H+ATPase activity due to chemical modification of the protein rather than changes in membrane fluidity and suggest that modification is away from the active site.

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