The HvSUT1 gene encodes a membrane transport protein which mediates the energy-dependent transport of saccharose (sucrose) across cell membranes against a concentration gradient.  Sucrose transporters are thought to be among the basic components of all higher plants, since saccharose is the universal transport form of all photoassimilates.

In barley tissue, messenger RNA that encodes the HvSUT protein was found at the central exchange point between the maternal (parent plant) and filial (grain) parts of the plant. Induction of the HvSUT1 gene is associated with an increase in sucrose content in the developing grain, with the production of enzymes that play a role in starch formation, and with starch accumulation in the endosperm during corn formation. The HvSUT1 protein, therefore, appears to be an important controlling element for the import of sucrose into the endosperm. The function and mode of action of this gene has been closely examined in expression studies on baking yeast. Apart from the transport of sucrose, the gene is not known to have any additional functions.