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Human Orexin B, also known as Hypocretin-2, is a 28-residue C-terminally amidated neuropeptide derived from the prepro-orexin precursor. It activates both OX1 and OX2 receptors but displays substantially greater affinity for OX2R in established human receptor assays.
Product Information
| Property | Specification |
|---|---|
| Sequence | Arg-Ser-Gly-Pro-Pro-Gly-Leu-Gln-Gly-Arg-Leu-Gln-Arg-Leu-Leu-Gln-Ala-Ser-Gly-Asn-His-Ala-Ala-Gly-Ile-Leu-Thr-Met-NH₂ |
| One-Letter Sequence | RSGPPGLQGRLQRLLQASGNHAAGILTM-NH₂ |
| Peptide Length | 28 amino-acid residues |
| Molecular Formula | C123H212N44O35S |
| Molecular Weight | Approximately 2899.36 Da |
| CAS No. | 205599-76-4 |
| C-Terminus | Met-NH₂ |
| Receptor Profile | OX1R and OX2R agonist; higher affinity for OX2R |
OX1R and OX2R Are Not Engaged Equally
Human Orexin B is capable of activating both receptor subtypes, but binding studies reported substantially stronger affinity for OX2R than OX1R. This receptor preference distinguishes it pharmacologically from Orexin A, which behaves as a more balanced endogenous agonist.
For subtype assignment, we recommend combining ligand pharmacology with receptor-selective antagonists, genetic controls or defined recombinant receptor systems rather than relying on Orexin B alone.
Linear Peptide Architecture
Unlike Orexin A, human Orexin B contains no cysteine residues and no disulfide bridges. The molecule is therefore a linear amidated peptide, providing a structurally simpler orexin scaffold for receptor SAR.
Research Applications
Human Orexin B supports OX1/OX2 receptor pharmacology, intracellular signaling studies, sleep-wake and arousal research, hypothalamic circuit experiments and comparison with species variants.
Frequently Asked Questions
Does human Orexin B activate only OX2R?
No. It activates both OX1R and OX2R but shows a strong preference for OX2R in established receptor assays.
Is Orexin B the same as Hypocretin-2?
Yes. The two names refer to the same mature peptide family member.