Na+-dependent,electroneutral l-ascorbate transport across brush border membrane vesicles from guinea pig small intestine

In brush border vesicles from guinea pig small intestine l-ascorbate transport is Na⁺-dependent and electroneutral (in the presence of Na⁺, as shown by its lack of response to either positive or negative Δψ across the membrane).l-Ascorbate transporter has the kinetic characteristics of a mobile carrier (K_m for l-ascorbate, 0.3 mM). d-Isoascorbate (erythorbate) seems to be another, but poorer, substrate of the same transporter.l-Ascorbate transport is subjected to heterologous inhibition by d-glucose.