Figure 3. Molecular structure of fast and long acting insulin analogs. P(B28) and K(B29) residues at the COO⁻ terminus of B chain are reversed in Insulin Lispro. Insulin Aspart has D residue in place of P at B28. K(B29) residue is changed to E, and N(B3) is substituted with K in Insulin Glulisin. Glargine has an addition of two dibasic aa (RR) at the COO⁻ end of B chain (B31 and B32) in addition to a substitution of N to G at position A21. B29K residue is attached to a fatty acid (myristic acid) in Insulin Detemir, which lacks T(B30) (LysB29 (N-tetradecanoyl)des(B30)). In Insulin Degludec, however, T(B30) is deleted and K(B29) has been coupled to a fatty acid (hexadecanedionic acid) via E (Glu) bridge.