Figure 2.

Processing of human pre‐proIAPP into the mature IAPP sequence. (A) The 89 amino acid residues of pre‐pro‐peptide, including the 22‐residue signal sequence which is shown in blue underlined font, and the flanking peptide regions of the pro‐hormone, which are illustrated in red italicized font. (B) The sequence of proIAPP showing the cleavage sites for PC2 at the N‐terminus of mature IAPP and PC1/3 after three residues (GKR) in the C‐terminal flanking region. (C) Amidation of the C‐terminal Tyr is a multi‐step process. CPE removes the KR pair of dibasic residues that remain after PC1/3 cleavage, and the glycine is the nitrogen donor for amidation by PAM