Related Experiment Video
Updated: Jul 18, 2026

Electric and Magnetic Field Devices for Stimulation of Biological Tissues
Published on: May 15, 2021
Determination of the subunit stoichiometry of a voltage-activated potassium channel
1Department of Cellular and Molecular Physiology, Harvard Medical School, Boston, Massachusetts 02115.
Abstract:
The voltage-activated K+, Na+ and Ca2+ channels are responsible for the generation and propagation of electrical signals in cell membranes. The K+ channels are multimeric membrane proteins formed by the aggregation of an unknown number of independent subunits. By studying the interaction of a scorpion toxin with coexpressed wild-type and toxin-insensitive mutant Shaker K+ channels, the subunit stoichiometry can be determined. The Shaker K+ channel is found to have a tetrameric structure. This is consistent with the sequence relationship between a K+ channel and each of the four internally homologous repeats of Na+ and Ca2+ channels.
Related Concept Videos
The Electrical Double Layer
Insulation Coordination
Capacitance: Single-Phase And Three-Phase Line
Single-Phase Lines
Consider a single-phase, two-wire transmission line with equal phase spacing energized by a voltage source. One conductor carries a uniform positive charge, while the other carries an equal negative charge. The capacitance C of the line can be derived from the voltage V between the conductors. For a one-meter section of the line, the capacitance is given...
Control of Power Flow
Power System Three-Phase Short Circuits
Generator Voltage Control

