Based on sequence homology of the hydrophobic transmembrane cores, the alpha subunits of voltage-gated potassium channels are grouped into 12 classes.

[1] The following is a list of the 40 known human voltage-gated potassium channel alpha subunits grouped first according to function and then subgrouped according to the Kv sequence homology classification scheme: slowly inactivating or non-inactivating rapidly inactivating Passes current more easily in the inward direction (into the cell, from outside).

These channels have been studied by X-ray diffraction, allowing determination of structural features at atomic resolution.

Genetic approaches include screening for behavioral changes in animals with mutations in K+ channel genes.

Typically, vertebrate voltage-gated K+ channels are tetramers of four identical subunits arranged as a ring, each contributing to the wall of the trans-membrane K+ pore.

[7] The high resolution crystallographic structure of the rat Kvα1.2/β2 channel has recently been solved (Protein Databank Accession Number 2A79​),[8] and then refined in a lipid membrane-like environment (PDB: 2r9r​).

They include the amino acid sequence (Thr-Val-Gly-Tyr-Gly) or (Thr-Val-Gly-Phe-Gly) typical to the selectivity filter of voltage-gated K+ channels.

Upon opening of the channel, conformational changes in the voltage-sensor domains (VSD) result in the transfer of 12-13 elementary charges across the membrane electric field.

This type of gating is mediated by a voltage-sensing domain that consists of the S4 alpha helix that contains 6–7 positive charges.