An extended kinetic analysis of valinomycin-induced Rb-transport through monoglyceride membranes

Knoll, Wolfgang; Stark, G.

doi:10.1007/bf01868578

Cited by 48 publications

(57 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This variation presumably originates from the difficulty to establish partition equilibrium between the membrane and the aqueous phase. The association rate constant k R is also found to be independent of the carrier concentration Co, but it shows a very pronounced variation with ion concentration c M. A decrease of k~ with increasing e2u has already been observed by Knoll and Stark (1975) for valinomycin-mediated rubidium transport in monoolein mem- branes; as a possible explanation they proposed that a finite number of sites for the complexation reaction exists which become saturated at high c M. Knoll and Stark (1975) determined the rate constants of the valinomycin/Rb + system at 10 ~ using the voltage-jump method. For the purpose of comparison, we have also carried out a few experiments at 10 ~ with the charge-pulse technique.…”

Section: Resultsmentioning

confidence: 56%

“…At 25 ~ where complexation between valinomycin and alkali ions in water is negligible up to cM= 1 M , c s could be set equal to the total carrier concentration c o in water. Only in the experiments with 1 M rubidium chloride at 10 ~ the complexation in water had to be taken into account; from the data of Knoll and Stark (1975) the complexation constant was estimated to be ~ 1.5 M -1. It is seen from Table 1 that the three relaxation amplitudes al, aa, a 3 and also the longest relaxation time (%) strongly depend on the concentrations c o and %t.…”

Section: Resultsmentioning

confidence: 99%

“…The kinetics of carrier-mediated ion transport through lipid bilayer membranes has been studied by electrical relaxation experiments (Stark, Benz, Ketterer & L~iuger, 1971;Benz, Stark, Janko & L~iuger, 1973;Gambale, Gliozzi & Robello, 1973;Benz & Stark, 1975;Hladky, 1975b;Knoll & Stark, 1975;Laprade, Ciani, Eisenman & Szabo, 1975;Sandblom, H~igglund & Eriksson, 1975). In these studies the voltage-jump (or voltageclamp) method has been used which consists in measuring the time course of the membrane current after a sudden displacement of the voltage.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Kinetic analysis of carrier-mediated ion transport by the charge-pulse technique

1976

View full text Add to dashboard Cite

The charge-pulse technique has been used previously for the study of quasi-stationary processes in membranes which required only a moderate time resolution. It is shown here that a time resolution of about 400 nsec may be achieved with this technique and that it may be applied to the kinetic analysis of carrier-mediated ion transport. By this method we have studied the transport of alkali ions through optically black monoolein membranes in the presence of the ion carrier valinomycin. All three relaxation processes that are predicted by theory have been resolved. From the relaxation times and the relaxation amplitudes the rate constants for the association (kR) and the dissociation (kD) of the ion-carrier complex, as well as the translocation rate constants of the complex (kMS) and the free carrier (kS) could be obtained. For 1 M Rb+ at 25 degrees C the values are kR=3 x 10(5) M(-1) sec(-1), kD=2 x 10(5) sec (-1), kMS=3 x 10(5) sec(-1), kS=4 x 10(4) sec(-1). The activation energies of the single rate constants which have been estimated from experiments at two different temperatures range between 50 and 90kJ/mol.

show abstract

Section: Resultsmentioning

confidence: 56%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Kinetic analysis of carrier-mediated ion transport by the charge-pulse technique

1976

View full text Add to dashboard Cite

show abstract

“…It is interesting to note that an entirely analogous voltage dependence of interfacial absorption of rubidium ions in doped bilayers has been recently postulated (Knoll & Stark, 1976). Model (e) is the hypothesis of Magleby & Stevens (1972).…”

Section: Kinetic Modelsmentioning

confidence: 80%

Relaxation experiments using bath‐applied suberyldicholine.

Adams¹

1977

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. The effect of step changes in membrane potential on the end-plate conductance change produced by bath-applied suberyldicholine was studied in voltage-clamped frog muscle fibres.2. The suberyldicholine-induced conductance increased exponentially from its previous equilibrium level to a new equilibrium level following a step hyperpolarization.3. For low suberyldicholine concentrations the time constant of this relaxation was independent of the concentration.4. For low suberyldicholine concentrations the voltage dependence of equilibrium conductance and relaxation time constants was identical.5. Bungarotoxin pretreatment did not affect the responses beyond a simple reduction in their amplitude.6. The conductance evoked by high suberyldicholine concentrations was less voltage-sensitive than that evoked by low concentrations.7. A new model for explaining noise and relaxation data is proposed. This postulates rate-limiting binding steps followed by a voltagedependent isomerization.

show abstract

“…Though the two approaches are equivalent in the ohmic or low field limit (Ciani, Eisenman, Laprade & Szabo, 1972), the latter is more appropriate to the description of nonlinearities of current-voltage characteristics at high applied electric field. The kinetic approach to carrier-mediated transport has been applied to other ionophorous antibiotics as well as valinomycin, and has been extended steadily in recent publications (Laprade, Ciani, Eisenman & Szabo, 1974;Benz & Stark, 1975;Eisenman, Krasne & Ciani, 1975;Hladky, 1975;Knoll & Stark, 1975).…”

mentioning

confidence: 98%

Modification of valinomycin-mediated bilayer membrane conductance by 4,5,6,7-tetrachloro-2-methylbenzimidazole

Kuo

Bruner

1976

J. Membrain Biol.

View full text Add to dashboard Cite

The compound 4,5,6,7-tetrachloro-2-methylbenzimidazole (TMB), has been found to markedly modify the steady-state valinomycin-mediated conductance of potassium (K+) ions through lipid bilayer membranes. TMB alone does not contribute significantly to membrane conductance, being electrically neutral in solution. In one of two classes of experiments (I), valinomycin is first added to the aqueous phases, then changes of membrane conductance accompanying stepwise addition of TMB to the water are measured. In a second class of experiments (II), valinomycin is added to the membrane-forming solution, followed by TMB additions to the surrounding water. In both cases membrane conductance shows an initial increase with increasing TMB concentration which is more pronounced at lower K+ ion concentration. At TMB concentrations in excess of 10(-5) M, membrane conductance becomes independent of K+ ion concentration, in contrast to the linear dependence observed at TMB concentrations below 10(-7) M. This transition is accompanied by a change of high field current-voltage characteristics from superlinear (or weakly sublinear) to a strongly sublinear form. All of these observations may be correlated by the kinetic model for carrier-mediated transport proposed by Läuger and Stark (Biochim. Biophys. Acta 211:458, 1970) from which it may be concluded that valinomycin-mediated ion transport is limited by back diffusion of the uncomplexed carrier at high TMB concentrations. Experiments of class I reveal a sharp drop of conductance at high (greater than 10(-5) M) TMB concentration, not seen in class II experiments, which is attributed to blocked entry of uncomplexed carrier from the aqueous phases. Valinomycin initially in the membrane is removed by lateral diffusion to the surrounding torus. The time dependence of this removal has been studied in a separate series of experiments, leading to a measured coefficient of lateral diffusion for valinomycin of 5 x 10(-6) cm2/sec at 25 degrees C. This value is about two orders of magnitude larger than the corresponding coefficient for transmembrane carrier diffusion, and provides further evidence for localization of valinomycin in the membrane/solution interfaces.

show abstract

An extended kinetic analysis of valinomycin-induced Rb-transport through monoglyceride membranes

Cited by 48 publications

References 18 publications

Kinetic analysis of carrier-mediated ion transport by the charge-pulse technique

Kinetic analysis of carrier-mediated ion transport by the charge-pulse technique

Relaxation experiments using bath‐applied suberyldicholine.

Modification of valinomycin-mediated bilayer membrane conductance by 4,5,6,7-tetrachloro-2-methylbenzimidazole

Contact Info

Product

Resources

About