Potassium-dependent activation of Kir4.2 K+channels

Activation of mitochondrial ATP-dependent potassium channels by nitric oxide.

BACKGROUND Nitric oxide (NO) has been implicated as a mediator of "second-window" ischemic preconditioning, and mitochondrial ATP-dependent K(+) (mitoK(ATP)) channels are the likely effectors. The links between NO and mitoK(ATP) channels are unknown. METHODS AND RESULTS We measured mitochondrial redox potential as an index of mitoK(ATP) channel opening in rabbit ventricular myocytes. The NO d...

Cumulative activation of voltage-dependent KVS-1 potassium channels.

In this study, we reveal the existence of a novel use-dependent phenomenon in potassium channels, which we refer to as cumulative activation (CA). CA consists of an increase in current amplitude in response to repetitive depolarizing step pulses to the same potential. CA persists for up to 20 s and is similar to a phenomenon called "voltage-dependent facilitation" observed in some calcium chann...

The Mechanism of Activation of Potassium Dependent and Potassium Independent Asparaginases from Common Bean (Phaseolus vulgaris)

L-asparaginases play an important role in nitrogen mobilization in plants. This study investigated the biochemical and biophysical properties of potassium dependent (PvAspG1) and potassium independent (PvAspG-T2) L-asparaginases from P. vulgaris. Previous studies revealed that PvAspG1 requires potassium for catalytic activation and crystal structure analysis suggested that Ser-118 in the activa...

Electrochemistry of Copper Activation of Sphalerite and Potassium Isobutyl Xanthate (KIBX) Synthesized Collectors Adsorption

Activation of Shaker Potassium Channels

This second of three papers, in which we functionally characterize activation gating in Shaker potassium channels, focuses on the properties of a mutant channel (called V2), in which the leucine at position 382 (in the Shaker B sequence) is mutated to valine. The general properties of V2's ionic and gating currents are consistent with changes in late gating transitions, in particular, with V2 d...