Mobilization of storage proteins in soybean seed (Glycine max L.) during germination and seedling growth

► Proteomic analysis showed temporal profiles of protein expression during soybean seed germination. ► Major proteins identified were subunits of glycinin and β-conglycinin. ► The acidic subunits of glycinin were rapidly degraded, but no obvious change in the basic chains. ► The degradation pattern of β-conglycinin appeared to be similar to that of glycinin but at a faster rate. ► The mobilization of their subunits is differentially regulated for seed germination and seedling growth.