High-affinity uptake of alpha-glucosides such as maltose, turanose, isomaltose, alpha-methylglucoside, maltotriose, palatinose, trehalose, melezitose and glucose. Acts with the concomitant transport of protons into the cell (symport system). By maltose and maltotriose (PubMed:10618490, PubMed:12210897, PubMed:8594329). Repressed by glucose (PubMed:10618490, PubMed:12210897, PubMed:8594329). Belongs to the major facilitator superfamily. Sugar transporter (TC 2.A.1.1) family.