Parathyroid hormone (1-31)

Also known as PTH(1-31)

An N-terminal PTH fragment retaining receptor-activating residues, used to study PTH1R agonism and signalling determinants.

Length: 31 amino acids
Half-life: Not well characterised
Mechanism: PTH(1-31) engages PTH1R through its N-terminal activation region and retained extracellular-domain binding determinants, supporting Gs-dependent adenylyl cyclase activation and cAMP formation. The balance between cAMP and other signalling outputs varies with peptide structure and assay context.
Studied in: PTH1R-transfected cells, osteoblast-lineage cultures and animal skeletal models are used to investigate cAMP signalling, receptor trafficking and fragment structure–activity relationships.

About Parathyroid hormone (1-31)

Parathyroid hormone (1-31) contains the first 31 residues of the 84-residue mature PTH sequence. Compared with PTH(1-34), it lacks residues 32 through 34 but preserves the extreme N-terminus required for efficient receptor activation. Studies of shorter PTH fragments helped map the sequence requirements for receptor binding and second-messenger generation. Importantly, the unmodified linear fragment should be distinguished from cyclised, substituted or amidated analogues that also use a 1-31 designation.

Its principal research target is PTH1R, a class B G protein-coupled receptor with an extracellular ligand-binding domain and a transmembrane activation core. PTH(1-31) can stimulate cAMP production, making it useful for examining how C-terminal shortening changes agonist behaviour. Claims of exclusive cAMP selectivity require caution, because other pathways depend on receptor abundance and assay sensitivity. Binding affinity, signalling potency, maximal response and internalisation are distinct properties and should be characterised separately.

Laboratory notes

Confirm whether the material is linear, cyclised, substituted or terminally modified; these structural differences can substantially change assay behaviour.
For reference human sequence material, monitor methionine oxidation when preparing stability samples or comparing stored aliquots.
Include an established PTH1R agonist comparator and measure both potency and maximal response rather than relying on a single concentration.

Storage and reconstitution basics: storage guide.

Questions about Parathyroid hormone (1-31)

Is PTH(1-31) necessarily a cyclic peptide?

No. Residue numbering specifies sequence boundaries, not cyclisation. Any covalent ring or substitution must be stated separately.

Which residues are missing relative to PTH(1-34)?

It lacks positions 32, 33 and 34 while retaining the native N-terminal activation region.

Does PTH(1-31) activate only cAMP signalling?

That cannot be assumed. cAMP activity is well established for this fragment class, but pathway selectivity needs direct testing with the exact peptide and receptor system.

Is Parathyroid hormone (1-31) for human use?

No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.

Related research peptides

All products are sold for laboratory research use only. Not for human consumption, not a medicine, not for diagnosing, treating or preventing any condition.