DPF2 and cystic fibrosis: In this study, the expression of SS4 (a starch synthase) associated with starch biosynthesis was up-regulated in CF-CG, but, at the same time, the expressions of amyloytic enzymes, such as AMY2 (α-amylase), BAM2 (β-amylase) and DPF2 (4-α-glucan transferase), were up-regulated (Figure 8A).