Compound record
Protirelin
TRH; TSH-releasing hormone; thyroliberin
Sequence
pGlu-His-Pro-NH2
EHP
Length
3
residues
Formula
C16H22N6O4
elemental composition
Molecular weight
362.39
g/mol · average mass
CAS number
24305-27-9
registry ID
PubChem CID
6387
PubChem ID
Length counts residues; formula and mass are the stored free-base values from cited sources; CAS and PubChem identify the substance in public registries. More detail: length & peptide bonds, molecular weight
Structure & modifications
Linear tripeptide. 1-letter E denotes the pyroglutamate precursor residue; display notation is authoritative.
Notes
Protirelin (TRH) is the tripeptide pGlu-His-Pro-NH2 — among the smallest hypothalamic releasing hormones and a textbook case of dual terminal modification.
- N-terminus: pyroglutamate (cyclized Gln)
- C-terminus: prolinamide
- 1-letter stand-in:
EHP— display notation is authoritative
| Tag on this record | Why |
|---|---|
| N-terminal pyroglutamate | Lactamized N-terminus |
| C-terminal amidation | Pro-NH2 |
| Classification: linear | No residue-to-residue macrocycle beyond the pyroglutamate lactam |
Do not mass-calculate TRH as free Glu-His-Pro-OH. Registry: CAS 24305-27-9, PubChem CID 6387.
Primary-source references
- PubChem CID 6387 — protirelin
- Burgus R. et al. Characterization of ovine hypothalamic hypophysiotropic TSH-releasing factor. Nature 1970.
- Nair R.M.G. et al. Structure of porcine thyrotropin-releasing hormone. Biochemistry 1970.