It is a manufactured form of human insulin where the amino acids lysine and proline have been switched at the end of the B chain of the insulin molecule. This switch of amino acids mimics Insulin-like growth factor 1 which also has lysine (K) and proline (P) in that order at positions 27 and 28.
Insulin lispro
Insulin glulisine
Insulin aspart
Insulin detemir
Insulin glargine
Lente insulin
Insulin degludec
Insulin degludec/liraglutide