B7-33 (single-chain relaxin-2 analog) / Studies

Synthetic analog · 27 amino acids · 2,986.5 Da

B7-33 (single-chain relaxin-2 analog) studies and research data

PepBank has 8 B7-33 studies with results. All of them gave B7-33, with 31 results, grouped by what the studies measured. In each group, results from studies in people come first. Data as of 2026-10-30.

Searches 31 results and 12 papers. Newer studies from Europe PMC

Results in people

0% of 31 results

Results in animals

74% of 31 results

Results in lab cells

26% of 31 results

From computer models

0% of 31 results

The molecule

B7-33 identity

Identifiers, parent molecule, targets and development stage, from curated data.

B7-33 contains 27 residues derived from relaxin-2 B-chain positions 7 to 33, with both cysteines replaced by serines. The C-terminus is amidated. It is an RXFP1 agonist. It differs from two-chain relaxin-2, serelaxin, acetylated B7-33, and lipidated derivatives.

Kind: Synthetic analog · 27 residues
Identifiers: PubChem CID162662592 (opens in a new tab)
Parent: Analog of Human relaxin-2 B chain · residues 31-57The 33-residue B-chain isoform corresponds to precursor positions 25-57. Its residues 7-33 align to positions 31-57. Cysteine-to-serine changes occur at analog positions 5 and 17.
Development: PreclinicalPublished sources describe preclinical development. No human therapeutic development phase was established. Source (opens in a new tab)

Targets

Molecular targets with action and evidence source
Target	Action	Evidence
Relaxin family peptide receptor 1RXFP1	Agonist	primary design paperSource (opens in a new tab)

Sequence and structure

Residues, differences from the parent, calculated properties and 3D structure. Source values and calculated values are shown separately.

Sequence

27 amino acids · 3 modifications

H-

VIKLGRELV

RAQIAIGMS

TWSKRSL

Parent: Human relaxin-2 B chain

No sequence is listed for the parent, so no alignment is shown.The 33-residue B-chain isoform corresponds to precursor positions 25-57. Its residues 7-33 align to positions 31-57. Cysteine-to-serine changes occur at analog positions 5 and 17.

Properties

From identity sources

Formula: C₁₃₁H₂₂₉N₄₁O₃₆S
Molecular weight: 2,986.5 g/mol
Monoisotopic mass: 2,984.707 Da

PubChem CID 162662592(opens in a new tab)retrieved 2026-10-21

Calculated from the sequence

pKa set

Average mass: 2,986.57 Da; Sum of ExPASy residue masses + water + C-amide · ExPASy Compute pI/Mw; FindMod
Monoisotopic mass: 2,984.7069 Da; Sum of ExPASy residue masses + water + C-amide · ExPASy FindMod
Isoelectric point (pI): 12.81; pH of zero net charge, EMBOSS pKa set · EMBOSS iep, Epk.dat
Net charge at pH 7.4: 4.94; Henderson-Hasselbalch, EMBOSS pKa set · EMBOSS iep, Epk.dat
GRAVY (hydropathy): 0.152; Mean Kyte-Doolittle hydropathy · Kyte and Doolittle 1982; Positive: hydrophobic on average.
Extinction coefficient, 280 nm (Cys reduced): 5,500 M⁻¹ cm⁻¹; 5500 x Trp + 1490 x Tyr · Pace et al. 1995 (ExPASy ProtParam)
Instability index: 42.40; Dipeptide instability weights (DIWV) · Guruprasad et al. 1990; Above 40: classed as possibly unstable (ExPASy).
Aliphatic index: 115.6; Mole % A + 2.9 V + 3.9 (I + L) · Ikai 1980
Boman index: 1.48 kcal/mol; Mean solubility value (negated) · Boman 2003; 2.48 or below: lower protein-binding potential (Boman).
Hydrophobic moment (μH): 0.673; Eisenberg scale, 100° per residue, best 11-residue window · Eisenberg et al. 1982, 1984
pI with each pKa set: EMBOSS 12.81Bjellqvist (ExPASy) 12.31IPC peptide 12.81IPC protein 12.14

Defined and validated for proteins; use with care for short peptides.
Assumes an ideal alpha helix. Many short peptides are not helical.

@pepdb/chem 0.2.0 · EMBOSS pKa set · ExPASy residue masses

Net charge by pH

pI 12.81 · Net charge at pH 7.4: 4.94

Point or use arrow keys

Henderson-Hasselbalch, EMBOSS pKa set, C-amide. Calculated, not measured.

Show as table

pH	Net charge
0	6.00
1	6.00
2	5.99
3	5.93
4	5.56
5	5.11
6	5.01
7	4.98
8	4.80
9	4.25
10	3.76
11	2.69
12	1.40
13	−0.27
14	−0.91

Composition

Hydrophobic41% (11)A I L M V
Aromatic4% (1)W
Positive19% (5)K R
Negative4% (1)E
Polar26% (7)Q S T
Special7% (2)G

27 residues. Each residue counts in one class; F and W count as aromatic.

A Ala2 · 7%

I Ile3 · 11%

L Leu3 · 11%

M Met1 · 4%

V Val2 · 7%

F Phe0 · 0%

W Trp1 · 4%

Y Tyr0 · 0%

H His0 · 0%

K Lys2 · 7%

R Arg3 · 11%

D Asp0 · 0%

E Glu1 · 4%

N Asn0 · 0%

Q Gln1 · 4%

S Ser5 · 19%

T Thr1 · 4%

C Cys0 · 0%

G Gly2 · 7%

P Pro0 · 0%

3D structure

PredictedAlphaFold DB · P04090

Loads the 3D viewer (3Dmol.js, about 150 KB) and the model file from AlphaFold DB (EMBL-EBI).

2D structure

B7-33 (single-chain relaxin-2 analog) has 27 residues. A full-atom drawing is hard to read at this size; the sequence view is the reference.

SMILES fromPubChem CID 162662592(opens in a new tab)

CC[C@H](C)[C@@H](C(=O)N[C@@H](CO)C(=O)NCC(=O)N[C@@H](CCSC)C(=O)N[C@@H](CO)C(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](CC1=CNC2=CC=CC=C21)C(=O)N[C@@H](CO)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](CO)C(=O)N[C@@H](CC(C)C)C(=O)N)NC(=O)[C@H](C)NC(=O)[C@H]([C@@H](C)CC)NC(=O)[C@H](CCC(=O)N)NC(=O)[C@H](C)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](C(C)C)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCC(=O)O)NC(=O)[C@H](CCCNC(=N)N)NC(=O)CNC(=O)[C@H](CO)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCCCN)NC(=O)[C@H]([C@@H](C)CC)NC(=O)[C@H](C(C)C)N

Helical wheel

An ideal alpha-helix projection. It shows where the hydrophobic residues fall if the peptide folds as a helix. It does not show that it does.

μH, residues shown: 0.354
μH, best 11-residue window: 0.673
Arrow direction: 50°
Residues: 27 · 2 rings of 18

HydrophilicHydrophobic

Eisenberg consensus (normalized) scale · + K, R · − D, E

Assumes an ideal α-helix: 100° per residue, 3.6 residues per turn. The arrow is the mean hydrophobic moment (Eisenberg et al. 1984) and points at the hydrophobic face.

Show as table

Position	Residue	Angle	Eisenberg consensus (normalized)
1	V	0°	1.08
2	I	100°	1.38
3	K	200°	-1.50
4	L	300°	1.06
5	S	40°	-0.18
6	G	140°	0.48
7	R	240°	-2.53
8	E	340°	-0.74
9	L	80°	1.06
10	V	180°	1.08
11	R	280°	-2.53
12	A	20°	0.62
13	Q	120°	-0.85
14	I	220°	1.38
15	A	320°	0.62
16	I	60°	1.38
17	S	160°	-0.18
18	G	260°	0.48
19	M	0°	0.64
20	S	100°	-0.18
21	T	200°	-0.05
22	W	300°	0.81
23	S	40°	-0.18
24	K	140°	-1.50
25	R	240°	-2.53
26	S	340°	-0.18
27	L	80°	1.06

Results by area

B7-33 results by year and outcome

Counts are exact and come from studies that gave the peptide.

Studies by year

8 of 12 studies have results (67%), published 2016 to 2023. Top row: every study. Bottom row: studies with results about B7-33 (single-chain relaxin-2 analog), by class. The rows use different scales.

Studies
Human
Animal
Lab
Computer model
Natural levels, tool or combination only

Studies12 in all, 2016 to 2025

Studies with results8 in all, 2016 to 2023

Retracted studies are left out. A study with results in two classes counts in both.

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

What the studies measured

People first in each area, then animals, then lab cells. Counts are exact and come from studies that gave the peptide.

B7-33 studies on heart and blood vessels

14 results · people 0 · animals 12 · lab 2

Top 3 of 14 results

In rats, B7‑33 increased bradykinin-mediated mesenteric artery relaxation compared with placebo through increased endothelium-derived hyperpolarization.European journal of pharmacology, 2017
In mice with heart ischemia-reperfusion injury, B7‑33 reduced infarct size compared with vehicle.Journal of the American Heart Association, 2020
In mice with cardiomyopathy, B7‑33 and relaxin reduced heart fibrosis to a similar extent.Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2023

B7-33 studies on receptors and cell signals

9 results · people 0 · animals 4 · lab 5

Top 5 of 9 results

In preclinical tests, B7‑33 activated receptor pairs and downstream pERK signaling.Chemical science, 2016
In mice with ureter obstruction, B7‑33 increased kidney matrix metalloproteinase-2 compared with untreated obstruction.FASEB journal, 2021
In cells with simulated ischemia-reperfusion injury, B7‑33 reduced the stress marker GRP78 at 50 and 100 nmol/L.Journal of the American Heart Association, 2020
In preclinical tests, B7‑33 activated signaling of the collagen-degrading enzyme MMP-2.Chemical science, 2016
In mice with ureter obstruction, B7‑33 reduced tissue inhibitor of metalloproteinase-1 compared with untreated obstruction.FASEB journal, 2021

B7-33 studies on pain

2 results · people 0 · animals 2 · lab 0

2 results

In mice with paw inflammation, B7‑33 briefly reduced mechanical sensitivity only in the inflamed paw at 30 minutes.Pain reports, 2021
In mice with paw inflammation, B7‑33 briefly reduced heat sensitivity only in the inflamed paw at 30 minutes.Pain reports, 2021