Detailed Explanation
An inactive peptide precursor that requires enzymatic cleavage to become biologically active. Propeptides serve as safety mechanisms: they prevent potentially harmful peptides from being active before reaching their target tissue. Proinsulin (86 amino acids) is cleaved in pancreatic β-cell secretory granules to yield mature insulin (51 aa, A+B chains) and C-peptide (31 aa).
Proenkephalin yields multiple copies of Met-enkephalin and Leu-enkephalin. Pro-opiomelanocortin (POMC, 241 aa) is a polyprotein precursor that yields ACTH, β-endorphin, and α/β/γ-MSH depending on which proteases process it in different tissues. C-peptide, once thought to be biologically inert, is now used clinically to measure endogenous insulin production in diabetic patients.
Key Facts
- An inactive peptide precursor that requires enzymatic cleavage to become biologically active.
- Propeptides serve as safety mechanisms: they prevent potentially harmful peptides from being active before reaching their target tissue.
- Proinsulin (86 amino acids) is cleaved in pancreatic β-cell secretory granules to yield mature insulin (51 aa, A+B chains) and C-peptide (31 aa).
- Proenkephalin yields multiple copies of Met-enkephalin and Leu-enkephalin.
- Pro-opiomelanocortin (POMC, 241 aa) is a polyprotein precursor that yields ACTH, β-endorphin, and α/β/γ-MSH depending on which proteases process it in different tissues.
- C-peptide, once thought to be biologically inert, is now used clinically to measure endogenous insulin production in diabetic patients.
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PeptideDefinition.com provides educational content about peptide science. Not medical advice. Consult a licensed healthcare provider for medical decisions.