Cytosolic alpha-glucanotransferase essential for the cytosolic metabolism of maltose, an intermediate on the pathway by which starch is converted to sucrose in leaves at night. Metabolizes maltose exported from the chloroplast and is specific for beta-maltose. May play a role in freezing tolerance. Temperature drop induces inactivation of DPE2 that leads to rapid accumulation of maltose, a solute that protects cells from freezing damage. Transfers a segment of a (1->4)-alpha-D-glucan to a new position in an acceptor, which may be glucose or a (1->4)-alpha-D-glucan. Inactivated in response to cold stress. Circadian-regulation with a peak in expression in the middle of the light period. Dwarf plants with yellowish leaves that accumulate large amounts of maltose. Increased tolerance to cold. Belongs to the disproportionating enzyme family.