Parathyroid hormone-related protein (107-139)

Also known as PTHrP(107–139); C-terminal PTHrP fragment

A 33-residue C-terminal PTHrP fragment containing osteostatin, used to dissect region-specific skeletal cell signalling.

Length: 33 amino acids
Half-life: Not well characterised
Mechanism: PTHrP(107–139) contains the osteostatin motif and is studied for signalling activities distinct from canonical N-terminal PTHrP activation of PTH1R. No definitive cognate receptor has been established, and signalling assignments depend on the experimental model.
Studied in: Laboratory investigations use osteoblast-lineage cultures, osteoclast-related assays and animal skeletal models to examine C-terminal PTHrP activity.

About Parathyroid hormone-related protein (107-139)

PTHrP(107–139) comprises residues 107 through 139 of mature parathyroid hormone-related protein, giving a total of 33 amino acids. Its N-terminal five residues form the osteostatin sequence, TRSAW. This fragment arose from efforts to separate the biological contributions of different PTHrP regions after recognition that the protein has activities beyond its N-terminal receptor-binding domain. Because PTHrP has multiple isoforms, the designation specifies a residue interval rather than the complete C-terminal region of every isoform.

Research with this fragment examines osteoblast-associated signalling, differentiation markers and interactions between skeletal cell populations. Unlike PTHrP(1–36), it lacks the established N-terminal PTH1R-activating sequence, so canonical receptor pharmacology should not be transferred to it without evidence. Comparisons with osteostatin can test whether an observed response maps to residues 107–111 or depends on the extended sequence. Peptide integrity is particularly relevant because proteolysis may generate shorter active fragments and complicate attribution of a response to the intact molecule.

Laboratory notes

Verify species, residue numbering and terminal chemistry against the reference sequence used in the intended study.
Assess peptide stability in the assay medium where possible, particularly when attributing activity to the intact 33-residue fragment.
Include osteostatin and an appropriate sequence control when testing whether activity depends on the embedded TRSAW motif.

Storage and reconstitution basics: storage guide.

Questions about Parathyroid hormone-related protein (107-139)

Why is this fragment 33 residues long?

Residue numbering is inclusive: 139 minus 107 plus one equals 33 amino acids.

Does the fragment contain osteostatin?

Yes. Residues 107–111 form osteostatin at the fragment's N-terminus, followed by a further 28 residues.

Can its activity be attributed entirely to osteostatin?

Not without direct comparison. The extended sequence can influence stability, molecular interactions and motif accessibility, while proteolysis can change the species present during an assay.

Is Parathyroid hormone-related protein (107-139) for human use?

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

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