PMID- 10987385
OWN - NLM
STAT- MEDLINE
DCOM- 20010201
LR  - 20131121
IS  - 1023-6597 (Print)
IS  - 1023-6597 (Linking)
VI  - 13
IP  - 5
DP  - 2000
TI  - Effect of phytohormones on the transmembrane translocation of protons in plasma 
      membrane vesicles from tubers of Solanum tuberosum L.
PG  - 617-24
AB  - Effects of phytohormones gibberellic acid (GA) and abscisic acid (ABA) on the 
      ATP-dependent transmembrane transport of protons were studied in plasma membrane 
      vesicles (PMVs) from non-dormant potato tubers. The uptake of H+ into PMVs was 
      assessed by the fluorescence quenching of acridine orange (AO) after the addition 
      of ATP to the incubation medium. Addition of ATP to the incubation medium led to 
      the instantaneous rise of the AO fluorescence intensity followed by its decrease. 
      The fluorescence quenching was not observed in the presence of either 
      protonophore CCCP or inhibitors of the membrane-bound H+-ATPase. It is concluded 
      that the ATP-induced quenching of the AO fluorescence resulted from the 
      accumulation of protons in PMVs due to the function of the plasma membrane-bound 
      H+-ATPase. Depending on their concentrations, GA and ABA either inhibited or 
      stimulated the ATP-driven H+ translocation across the vesicle membrane. The 
      growth-stimulating hormone GA at concentrations of 10(-9)-10(-5) M increased the 
      initial rate of the fluorescence quenching, whereas 10(-4) M GA slightly 
      inhibited the H+ translocation. The growth inhibitor ABA at a concentration of 
      10(-9) M slightly increased the rate of the proton accumulation in PMVs; at 
      higher concentrations (10(-8)-10(-4) M), ABA inhibited the H+ translocation. 
      Acetic acid, which has pK similar to pK of GA and ABA, did not influence the 
      ATP-dependent H+ accumulation in PMVs, suggesting the hormone-specific action of 
      GA and ABA on the H+-ATPase activity. In the presence of DCC, which completely 
      inhibited the accumulation of H+, GA and ABA did not affect the passive proton 
      efflux from PMVs. It is proposed that the mechanisms of the regulatory effects of 
      phytohormones may involve modification of H+-ATPase activity leading to changes 
      in the electrochemical gradient of H+ across the plasma membrane.
FAU - Ladyzhenskaya, E P
AU  - Ladyzhenskaya EP
AD  - Bakh Institute of Biochemistry, Russian Academy of Sciences, Moscow. 
      inbio@glas.apc.org
LA  - eng
PT  - Journal Article
PL  - Switzerland
TA  - Membr Cell Biol
JT  - Membrane & cell biology
JID - 9517472
RN  - 0 (Gibberellins)
RN  - 0 (Plant Growth Regulators)
RN  - 0 (Protons)
RN  - 72S9A8J5GW (Abscisic Acid)
RN  - BU0A7MWB6L (gibberellic acid)
SB  - IM
MH  - Abscisic Acid/*metabolism
MH  - Biological Transport
MH  - Cell Membrane/metabolism
MH  - Gibberellins/*metabolism
MH  - Plant Growth Regulators/*metabolism
MH  - Protons
MH  - Solanum tuberosum/*metabolism
EDAT- 2000/09/15 11:00
MHDA- 2001/02/28 10:01
CRDT- 2000/09/15 11:00
PHST- 2000/09/15 11:00 [pubmed]
PHST- 2001/02/28 10:01 [medline]
PHST- 2000/09/15 11:00 [entrez]
PST - ppublish
SO  - Membr Cell Biol. 2000;13(5):617-24.