An enzyme that rapidly inactivates GLP-1 and other incretin hormones—the reason native GLP-1 only lasts minutes in your blood.Dipeptidyl peptidase-4 (DPP-IV/CD26) is a serine protease that cleaves N-terminal dipeptides from substrates with proline or alanine at position 2. DPP-IV rapidly inactivates GLP-1 (t½ ~2 min), GIP, GLP-2, PYY, and neuropeptide Y. DPP-IV inhibitors (gliptins) extend incretin half-life for diabetes treatment. Long-acting GLP-1 receptor agonists (semaglutide, tirzepatide) incorporate structural modifications (fatty acid conjugation, amino acid substitutions) that resist DPP-IV cleavage, extending half-life from minutes to days or weeks.E↑ Top