Facilitative hexose transporter that mediates the transport of glucose, fructose and galactose. Likely mediates the bidirectional transfer of glucose across the plasma membrane of hepatocytes and is responsible for uptake of glucose by the beta cells. D-glucose(out) = D-glucose(in) D-fructose(out) = D-fructose(in) L-dehydroascorbate(out) = L-dehydroascorbate(in) D-galactose(in) = D-galactose(out) D-glucose and maltose competitively inhibit fructose transport. D-glucose, D-fructose and maltose inhibit deoxyglucose transport. Belongs to the major facilitator superfamily. Sugar transporter (TC 2.A.1.1) family. Glucose transporter subfamily.