| antiporters | Membrane glycoproteins that transport substrates across the membrane in a tightly coupled stoichiometric manner. The stoichiometry of influx of one substrate and the efflux of another is fixed by a single transport catalytic cycle; that is, the membrane is not freely permeable to either substrate. Antiporters mediate secondary active transport, using the electrochemical energy of a primary gradient (mostly for sodium) that is built up by an ATP-consuming transporter (mostly sodium, potassium atpase) to maintain transmembrane gradients for other electrolytes or metabolic substrates. (12 Dec 1998) |
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