Hemopressin

Hemopressin

Names
IUPAC name (2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-6-amino-2-[[(2S)-2-[[(2S)-4-amino-2-[[(2S)-3-methyl-2-[[(2S)-pyrrolidine-2-carbonyl]amino]butanoyl]amino]-4-oxo-butanoyl]amino]-3-phenyl-propanoyl]amino]hexanoyl]amino]-3-phenyl-propanoyl]amino]-4-methyl-pentanoyl]amino]-3-hydroxy-propanoyl]amino]-3-(1H-imidazol-5-yl)propanoic acid
Identifiers
CAS Number	568588-77-2 N[PubChem]
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL510801
ChemSpider	23327737 N
PubChem CID	44560117
CompTox Dashboard (EPA)	DTXSID301029393
InChI InChI=1S/C53H77N13O12/c1-30(2)22-37(47(71)65-42(28-67)51(75)64-41(53(77)78)25-34-27-56-29-58-34)60-49(73)39(24-33-16-9-6-10-17-33)61-46(70)36(18-11-12-20-54)59-48(72)38(23-32-14-7-5-8-15-32)62-50(74)40(26-43(55)68)63-52(76)44(31(3)4)66-45(69)35-19-13-21-57-35/h5-10,14-17,27,29-31,35-42,44,57,67H,11-13,18-26,28,54H2,1-4H3,(H2,55,68)(H,56,58)(H,59,72)(H,60,73)(H,61,70)(H,62,74)(H,63,76)(H,64,75)(H,65,71)(H,66,69)(H,77,78)/t35-,36-,37-,38-,39-,40-,41-,42-,44-/m0/s1 N Key: DUTLYPZZJJBEAJ-QISMNGAHSA-N N InChI=1/C53H77N13O12/c1-30(2)22-37(47(71)65-42(28-67)51(75)64-41(53(77)78)25-34-27-56-29-58-34)60-49(73)39(24-33-16-9-6-10-17-33)61-46(70)36(18-11-12-20-54)59-48(72)38(23-32-14-7-5-8-15-32)62-50(74)40(26-43(55)68)63-52(76)44(31(3)4)66-45(69)35-19-13-21-57-35/h5-10,14-17,27,29-31,35-42,44,57,67H,11-13,18-26,28,54H2,1-4H3,(H2,55,68)(H,56,58)(H,59,72)(H,60,73)(H,61,70)(H,62,74)(H,63,76)(H,64,75)(H,65,71)(H,66,69)(H,77,78)/t35-,36-,37-,38-,39-,40-,41-,42-,44-/m0/s1 Key: DUTLYPZZJJBEAJ-QISMNGAHBC
SMILES CC(C)C[C@@H](C(=O)N[C@@H](CO)C(=O)N[C@@H](Cc1cnc[nH]1)C(=O)O)NC(=O)[C@H](Cc2ccccc2)NC(=O)[C@H](CCCCN)NC(=O)[C@H](Cc3ccccc3)NC(=O)[C@H](CC(=O)N)NC(=O)[C@H](C(C)C)NC(=O)[C@@H]4CCCN4
Properties
Chemical formula	C53H77N13O12
Molar mass	1088.25838
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Hemopressin (Hp) is an alpha hemoglobin fragment with the sequence PVNFKFLSH, originally identified in extracts of rat brain using an enzyme capture technique.^[1] It binds cannabinoid receptors, acting as an inverse agonist at CB₁ receptors.^[2] Longer forms of hemopressin containing 2-3 additional amino acids on the N-terminus have been identified in extracts of mouse brain. These longer hemopressin peptides, named RVD-Hpα and VD-Hpα, bind to CB1 receptors and were originally reported to be agonists.^[3] In addition to the Hp peptides from alpha hemoglobin, a related peptide from beta hemoglobin has been found in mouse brain extracts; this peptide, named VD-Hpβ, is also an agonist at CB1 cannabinoid receptors.^[3] Hemopressin is not an endogenous peptide but rather an extraction artefact.^[4] The only endogenous peptide found endogenously at physiological conditions is RVD-hemopressin (pepcan-12), which has more recently been shown to be a negative allosteric modulator of CB1 receptors and positive allosteric modulator of CB2 receptors.^[4][5] RVD-hemopressin (pepcan-12) is generated from a pro-peptide called pepcan-23 and these peptides are exclusively found in noradrenergic neurons in the brain and in the adrenal medulla.^[6]

The original Hp peptide reduces sensitivity to painful stimuli in an experimental model of hyperalgesia.^[7] Hp also reduces food intake in mice.^[8] However, it remains to be shown if Hp is an endogenous brain peptide. The original purification used boiling acid to extract the peptide from rat brain, and hot acid can specifically cleave D-P bonds. The N-terminally-extended forms RVD-Hpα and VD-Hpα may represent the true endogenous forms.^[9]