Membrane Transporter Glossary

Antiporter: A transporter that moves two substrates in opposite directions across the membrane.

Channel: Membrane proteins that are involved in particular transport of ions or uncharged molecules down their electrochemical potential gradient.

Exporter: A transporter that functions in the outward direction.

Importer: A transporter that functions in the inward direction.

Primary active transporter: A transporters functioning through various chemical or photochemical reactions as energy resources.

Secondary active transporter: A transporter using electrochemical potential gradients (e.g., H⁺ and Na⁺) as energy sources.

Symporter: A transporter that co-transports two separate substrates in the same direction.

TMD: Transmembrane domain.

Transporter: Proteins that span the lipid bilayer of membranes, constituting transmembrane channels along with hydrophilic amino acid side chains, and functioning in the uptake of nutrients and removal of cellular wastes.

Uniporter: A transporter that mediates the unidirectional movement of a single substrate across the membrane.