Figure 3. Two kinetic models of Na-K-2Cl cotransport.

A. Glide symmetry model where a Na⁺ ion binding first on the cotransporter in the outside facing configuration is the first ion coming off in the inward facing configuration. B. Alternative model with more conventional kinetics where Cl⁻ binds first followed by Na⁺, the second Cl⁻, and K⁺. Partial reactions or slippages which are electroneutral in nature (e.g. NaCl movement) are allowed. See text for details and references.