Figure 3.

Schematic illustration of insulin analogs and comparison of the sequences with human insulin and IGF-1. Single-letter codes of amino acids are used. Vacant residues in insulin B chain are shown as empty circles; numbers represent their positions in the insulin B chain sequence. The respective sequence of human IGF-1 and its location in the amino acid chain is shown. Expected downshift of the B25 residue (and residues upward) due to the presence of d-His at B24 (DH) is indicated by bending of the connecting line. DOI, des-(B23-B30)-octapeptide-insulin. -DTI-NH₂, des-(B27-B30)-tetrapeptide-B26-carboxamide insulin.