Na+-to-sugar stoichiometry of SGLT3 Article

Díez-Sampedro, A, Eskandari, S, Wright, EM et al. (2001). Na+-to-sugar stoichiometry of SGLT3 . 280(2 49-2), 10.1152/ajprenal.2001.280.2.f278

cited authors

  • Díez-Sampedro, A; Eskandari, S; Wright, EM; Hirayama, BA


  • Sodium-glucose cotransporters (SGLTs) mediate active transport of sugar across cell membranes coupled to Na+, by using the electrochemical gradient as a driving force. In the kidney, there is evidence for two kinds of cotransporters, a high-affinity, low-capacity system, and a low-affinity, high-capacity system, with differences in substrate specificity and kinetics. Three renal SGLT clones have been identified: SGLT1 corresponding to the high-affinity system, and SGLT2 and SGLT3 with properties reminiscent of the low-affinity system. We have determined the stoichiometry of pig SGLT3 (pSGLT3) by using a direct method, comparing the substrate-induced inward charge to 22Na or [14C]α-methyl-D-glucopyranoside uptake in the same oocyte. pSGLT3 stoichiometry is 2 Na+:1 sugar, the same as that for SGLT1, but different from SGLT2 (1:1). The Na+ Hill coefficient for SGLT3 is ∼1.5, suggesting low cooperativity between Na+ binding sites. Thus SGLT3 has functional characteristics intermediate between SGLT1 and SGLT2, so, whereas SGLT3 stoichiometry is the same as that for SGLT1 (2:1), sugar affinity and specificity are similar to SGLT2.

publication date

  • January 1, 2001

Digital Object Identifier (DOI)


  • 280


  • 2 49-2