The electrochemical proton potential ofBacillus alcalophilus

Monovalent cation/proton antiporters in membrane vesicles from Bacillus alcalophilus.

Alkalophilic bacilli maintain a cytoplasmic pH that is lower than optimal external pH values. The current study, using isolated membrane vesicles from Bacillus alcalophilus, indicates that respiration results in proton extrusion as in other organisms. Cation/proton antiporters then catalyze inward proton movements. Upon energization with ascorbate/N,N,N',N'-tetramethyl-p-phenylenediamine, Na'-l...

Dissipation of the Proton Electrochemical Potential in lntact Chloroplasts'

The potency of various uncouplers for collapsing the lightinduced pH gradient across thylakoid membranes in intact chloroplasts was investigated by time-resolved optical spectroscopy. The thylakoid transmembrane pH gradient (ApH) was monitored indirectly by measuring the rate of cytochrome (Cyt) f reduction following a light flash of sufficient duration to create a sizable ApH. The results show...

Components of the proton electrochemical potential gradient in Anabaena variabilis.

Measurement of the Electrochemical Proton Gradient in

The pH gradient and membrane potential of submitochondrial particles from bovine heart were estimated by the uptake of ["C]ethylamine and ["'Cl]perchlorate, using filtration through a glass fiber prefilter and Millipore filter without washing to separate the vesicles from the medium. An external volume probe of ['HI sucrose was also used. Internal volume of the vesicles was measured by the exte...

Electrochemical Potential Spectroscopy: A New Electrochemical Measurement