Peptide Reference Desk
PYY(3–36) vs PYY(1–36): two missing residues change the receptor profile
DPP-4 removes the N-terminal Tyr-Pro dipeptide from PYY(1–36), producing PYY(3–36) and shifting receptor selectivity and analytical requirements.
The processing step is the key fact
PYY is secreted as a 36-residue amidated peptide. DPP-4 removes the N-terminal Tyr-Pro dipeptide to generate PYY(3–36). The products differ by only two residues, yet the processing changes receptor preference: PYY(1–36) engages several Y-receptor subtypes, whereas PYY(3–36) is more selective for Y2.
An assay must distinguish the forms
“Total PYY” and “PYY(3–36)” are not interchangeable measurements. Immunoassay cross-reactivity, ex-vivo DPP-4 activity and sample-handling delay can alter the apparent ratio after collection.
| Control point | Why it matters |
|---|---|
| Protease inhibition | Limits conversion during sample handling |
| Form-specific calibration | Separates total from active-form reporting |
| LC-MS resolution | Confirms the two-residue mass difference |
| C-terminal amidation | Part of the declared molecular identity |
Do not call one simply “the active PYY”
Activity depends on receptor, tissue and experimental question. PYY(3–36) is prominent in appetite literature, while PYY(1–36) retains broader receptor pharmacology. The professional record names the form rather than relying on a context-dependent adjective.
Verify with primary records
Use the primary paper, current regulator label or lot-linked analytical file for the claim it supports. A search result is a route to evidence, not the evidence itself.