The potential range of the transition region between the diffusion-limited reduction to oxidation of hydrogen peroxide depends strongly on the nature of the cation of the supporting alkaline electrolyte. Non-covalent interactions between the hydrated alkali metal cations and chemisorbed OH species on platinum influence the potential-dependent reaction kinetics.

The effect of membrane surface potential on the uptake of tryptamine, an organic cation, by rat intestinal brush-border membrane vesicles was investigated. In the presence of an inside-negative K(+)-diffusion potential, the manner of initial uptake of tryptamine appeared to be pH-dependent and the uptake in the acidic medium was lower than that in the neutral medium. Changes in surface potentia...

Isolated beef heart mitochondria, swollen in 100 mM Nat or K+ nitrate, contract and extrude the accumulated salt in a respiration-dependent reaction. The reaction is more rapid and extensive in Na+ than in K+ nitrate. Contraction is inhibited by uncouplers and by reagents, such as valinomytin and gramicidin, which increase transmembrane permeability to cations. The rate and extent of contractio...

Ionizations of 2-substituted l,l-dimethyl-3,4-methano-1,2,3,4-tetrahydronaphthalen-2-ols (8) (3,3-dimethylbenzobicyclo[4.1 .O]heptan-2-ols) in FS03H/S02CIF at -1 30 O C do not yield the corresponding 2-cations but benzylic (4-) cations 10 as a result of cyclopropylcarbinyl~yclopropylcarbinyl rearrangements. At higher temperatures, 10a and 10b undergo a further series of rearrangements to yield ...

We have studied glutamate release from synaptic vesicles in permeabilized synaptosomes, which were preloaded with [3H]glutamate in an ATP-dependent manner. The release was found to be calcium-dependent and to require a heat-labile cytosolic macromolecule factor for maximum activity. Maximal release occurred at 5 microM free Ca2+ and within 5 min. Of the other divalent cations tested, only bariu...

Hypokalemic periodic paralysis and normokalemic periodic paralysis are caused by mutations of the gating charge-carrying arginine residues in skeletal muscle Na(V)1.4 channels, which induce gating pore current through the mutant voltage sensor domains. Inward sodium currents through the gating pore of mutant R666G are only approximately 1% of central pore current, but substitution of guanidine ...

Optoelectronic devices based on layered perovskites containing fluorinated cations display a well-documented improved stability and enhanced performance over non-fluorinated cations. The effect of fluorination the crystal structure photophysics, however, has received limited attention up until now. Here, 3-fluorophenethylammonium lead iodide ((3-FPEA)2PbI4) single crystals are investigated thei...