Neuropeptides and derived fragments

Compound

Human corticotropin-releasing factor (1–41) amide

Corticorelin (human/rat sequence) is a 41-residue peptide with a free N terminus and an amidated C-terminal isoleucine.

hCRF · Human corticotropin-releasing factor · Rat corticotropin-releasing factor

Compound

DSIP

DSIP is a synthetic nonapeptide, Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, first isolated and sequenced in 1978.

DSIP · Delta-sleep-inducing peptide

Compound

Galanin (human 1-30)

Galanin is a thirty-residue human neuropeptide acting through the galanin receptor family, and the reference ligand against which spexin's receptor selectivity is measured.

GAL · Galanin(1-30)

Compound

Gonadorelin (GnRH-I)

Gonadorelin is the ten-residue hypothalamic releasing hormone GnRH-I, carrying an N-terminal pyroglutamate and a C-terminal amide.

GnRH-I · Gonadotropin-releasing hormone · LHRH · LH-RH

Compound

Met-enkephalin

Met-enkephalin is a linear five-residue peptide with the sequence Tyr-Gly-Gly-Phe-Met and free amino and carboxyl termini.

Methionine enkephalin · Methionine-enkephalin · [Met5]enkephalin

Compound

Oxytocin

Oxytocin is a mature nine-residue peptide with an intramolecular disulfide and a terminal carboxamide. This identity record is scoped to the Leu8 form.

Compound

PACAP-38

PACAP-38 is a linear 38-residue peptide with a free N-terminal histidine and a C-terminal lysinamide.

PACAP 38

Compound

TRH (thyrotropin-releasing hormone)

Protirelin is a tripeptide comprising L-pyroglutamyl, L-histidyl and L-prolinamide units in that order.

Thyrotropin-releasing hormone · TRH · Thyrotropin-releasing factor · TRF

Compound

CCK-8 (sulfated)

Sincalide is a linear eight-residue peptide with Tyr2 O-sulfation, a free N terminus and a C-terminal phenylalanine amide.

Sulfated cholecystokinin octapeptide · O-sulfated CCK-8

Compound

Spadin

Spadin is a sortilin-propeptide-derived peptide reported to interact with sortilin and to inhibit the TREK-1 potassium channel, and the parent design from which PE 22-28 was derived.

Compound

Spexin

Spexin is an endogenous fourteen-residue amidated neuropeptide identified by computational screening of the human proteome, and a ligand of galanin receptors 2 and 3.

SPX · Spexin-1 · NPQ

receptor

Corticotropin-releasing factor receptor 1

CRFR1 is a class B G-protein-coupled receptor. Independent receptor-expression and receptor-complex studies identify binding of the human/rat-sequence corticotropin-releasing factor peptide.

receptor

Galanin receptors

The galanin receptor family comprises three G protein-coupled receptors. GALR1 and GALR3 signal through Gi/o, while GALR2 signals mainly through Gq/11. Spexin activates GALR2 and GALR3 but not GALR1 in the reported ligand panel. Structural studies compared galanin-bound GALR1-Go and GALR2-Gq with spexin-bound GALR2-Gq, providing evidence for ligand recognition and subtype-dependent coupling.

receptor

Opioid receptors

Receptor sites characterized by direct opioid-ligand binding experiments. Historical peptide studies establish receptor binding without necessarily resolving a modern receptor subtype.

receptor

PACAP and VIP receptors

Receptor relationships involving PAC1, VPAC1 and VPAC2, with each ligand’s tested receptor subtype identified separately.

receptor

Thyrotropin-releasing hormone receptor

A class A G-protein-coupled receptor. Independent structural studies report the defined TRH tripeptide bound to human TRHR in receptor–G-protein complexes.

receptor

Cholecystokinin 1 receptor

The cholecystokinin 1 receptor is a class A G-protein-coupled receptor. Independent structural studies identify sulfated CCK-8 bound to this receptor.