Probable alpha-amylase that does not seem to be required for breakdown of transitory starch in leaves. Endohydrolysis of (1->4)-alpha-D-glucosidic linkages in polysaccharides containing three or more (1->4)-alpha-linked D-glucose units. Expressed in developing siliques. Circadian-regulated, with a peak in expression at the beginning of the light period. No visible phenotype under normal growth conditions. Belongs to the glycosyl hydrolase 13 family.