B7-33 (6mg) Peptide – Research-Grade Relaxin Analogue

B7-33 (6mg) is a synthetic, single-chain peptide analogue derived from the B-chain region of human H2 relaxin. Also described as a relaxin-2 B-chain mimetic, B7-33 has been developed as a simplified peptide model for investigating selected biological activities associated with the relaxin signalling system.

B7-33 is particularly notable for its interaction with relaxin family peptide receptor 1 (RXFP1). Research has characterised B7-33 as a functionally selective RXFP1 agonist that preferentially activates ERK-related signalling rather than producing the same signalling profile as full-length H2 relaxin. Experimental studies have subsequently investigated B7-33 in areas including fibrosis, vascular biology, tissue remodelling and cardiovascular research.

The 6mg research format is supplied as a lyophilised powder, with the referenced product listing reporting a stated purity of greater than 99%. B7-33 is intended for controlled laboratory research and should not be represented as an approved medicine or established treatment for fibrosis, cardiovascular disease or any other medical condition.

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What Is B7-33?

B7-33 is a synthetic peptide derived from the B-chain of human H2 relaxin, a naturally occurring peptide hormone involved in a range of physiological signalling processes.

Unlike full-length H2 relaxin, which has a complex two-chain structure connected by disulphide bonds, B7-33 was designed as a smaller single-chain linear peptide. This simplified structure was developed through structure-activity research to retain selected relaxin-like biological activity while producing a more readily synthesised peptide analogue.

Research published on B7-33 describes it as a functionally selective agonist of RXFP1. In cellular models expressing RXFP1, B7-33 preferentially activated the ERK pathway over cAMP signalling. This distinctive signalling profile is one of the main reasons the peptide continues to attract scientific interest.

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B7-33 (6mg) Product Highlights

• Product name: B7-33
• Quantity: 6mg
• Peptide type: Synthetic relaxin analogue
• Structural basis: B-chain derivative of human H2 relaxin
• Structure: Single-chain peptide
• Primary receptor of interest: RXFP1
• Primary research area: Relaxin receptor signalling
• Additional research areas: Fibrosis, vascular biology, tissue remodelling and cardiovascular research
• Product form: Lyophilised powder
• Stated purity: >99%
• Intended application: Laboratory and research use

The product format and stated purity are based on the referenced Core Peptides product listing. :contentReference[oaicite:3]{index=3}

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B7-33 and H2 Relaxin

To understand B7-33, it is useful to first understand H2 relaxin. Human H2 relaxin, commonly referred to simply as relaxin-2, is a peptide hormone belonging to the relaxin peptide family.

Relaxin signalling has been investigated in connection with vascular function, tissue remodelling, extracellular-matrix regulation and reproductive physiology. The biological actions of relaxin peptides are mediated through a family of receptors known as relaxin family peptide receptors, including RXFP1 and RXFP2.

Full-length H2 relaxin has a complex insulin-like structure consisting of A and B chains. Researchers investigating structure-function relationships sought to determine whether a smaller section of the molecule could reproduce selected activities of the complete hormone.

This research ultimately led to the development of B7-33, a single-chain analogue based on the relaxin B-chain region. Published research demonstrated that B7-33 retained significant RXFP1 agonist activity while displaying a distinct signalling profile.

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B7-33 and RXFP1 Receptor Signalling

RXFP1, or relaxin family peptide receptor 1, is a G protein-coupled receptor that serves as a major receptor for H2 relaxin.

Activation of RXFP1 can engage several intracellular signalling pathways. Research on B7-33 has focused particularly on the balance between cyclic AMP (cAMP) and ERK1/2 signalling.

A foundational study described B7-33 as a functionally selective RXFP1 agonist because it preferentially stimulated the pERK pathway rather than producing the same degree of cAMP activation associated with H2 relaxin.

This selective signalling behaviour makes B7-33 valuable for researchers studying how individual receptor pathways contribute to the biological effects of relaxin.

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B7-33 and ERK Signalling

Extracellular signal-regulated kinases (ERK1/2) are intracellular signalling proteins involved in numerous cellular processes, including proliferation, differentiation, survival and tissue responses to external stimuli.

Research has shown that B7-33 preferentially activates the ERK pathway following RXFP1 engagement. This signalling pattern differs from the broader activity of full-length H2 relaxin and has been proposed as one explanation for the peptide’s observed anti-fibrotic effects in experimental models.

In research models, RXFP1 activation by B7-33 has also been associated with downstream activation of pathways involving matrix metalloproteinase-2 (MMP-2), an enzyme involved in extracellular-matrix remodelling.

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B7-33 and Anti-Fibrotic Research

One of the principal areas of B7-33 research is fibrosis. Fibrosis is characterised by excessive accumulation and remodelling of extracellular-matrix components, particularly collagen, which can alter the structure and function of affected tissues.

Researchers have investigated whether selective RXFP1 activation by B7-33 can influence pathways involved in fibrotic remodelling. In preclinical models involving cardiac and pulmonary disease, B7-33 demonstrated anti-fibrotic activity and reduced pathological tissue remodelling.

The proposed mechanism involves RXFP1 signalling, ERK1/2 activation and increased activity of extracellular-matrix-remodelling enzymes such as MMP-2.

These findings have made B7-33 an important experimental compound for studying the molecular mechanisms controlling fibrosis and tissue remodelling.

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B7-33 and Cardiac Fibrosis Research

Cardiac fibrosis involves excessive deposition of connective tissue within the heart and can occur following myocardial injury or in chronic cardiovascular disease.

Researchers have investigated B7-33 in experimental models of cardiac injury and adverse cardiac remodelling. A study published in the Journal of the American Heart Association examined B7-33 following myocardial ischaemia-reperfusion injury in mice.

The researchers reported that B7-33 treatment reduced infarct size and preserved fractional shortening compared with vehicle-treated animals in the experimental model. The study described B7-33 as a synthetic analogue of the relaxin-2 B-chain that preferentially activates ERK1/2 signalling through RXFP1. :contentReference[oaicite:8]{index=8}

These findings provide a basis for further investigation into RXFP1-mediated signalling following cardiovascular injury, although results from animal models cannot be assumed to demonstrate equivalent effects in humans.

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B7-33 and Myocardial Injury Research

Myocardial ischaemia-reperfusion injury can trigger inflammation, cell damage and subsequent structural remodelling of cardiac tissue. Researchers have therefore explored compounds that may influence the repair and remodelling processes that follow cardiac injury.

In a mouse model of myocardial ischaemia-reperfusion injury, B7-33 was investigated for its effects on infarct size and cardiac function. The study reported a smaller infarct size and improved fractional shortening in B7-33-treated animals compared with the vehicle group.

This research contributes to a broader scientific interest in relaxin-derived peptides as experimental tools for studying cardiovascular tissue responses.

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B7-33 and Vascular Research

H2 relaxin has been investigated extensively for its effects on vascular function, and researchers have examined whether B7-33 can reproduce selected vascular actions of the parent hormone.

A published experimental study compared B7-33 with recombinant human relaxin-2 and investigated vascular responses in animal models. The research found that B7-33 could reproduce several vasoprotective effects associated with human relaxin-2.

These observations make B7-33 relevant to laboratory research into vascular signalling, blood-vessel function and the role of RXFP1 in cardiovascular biology.

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B7-33 and Tissue Remodelling

Healthy tissue continuously undergoes extracellular-matrix turnover. This process involves the synthesis, organisation and degradation of structural proteins such as collagen.

Excessive or dysregulated matrix deposition can contribute to fibrosis and impaired organ function. B7-33 has attracted interest because its RXFP1-mediated signalling has been associated with pathways involved in matrix remodelling.

In experimental models, B7-33 has been associated with increased activity of MMP-2, an enzyme involved in the breakdown and remodelling of extracellular-matrix components.

Research into these mechanisms may help scientists better understand how selective receptor agonists can influence pathological tissue remodelling.

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B7-33 and Lung Fibrosis Research

The anti-fibrotic properties of B7-33 have also been investigated in pulmonary models. Fibrotic remodelling of lung tissue can substantially alter the architecture and mechanical properties of the respiratory system.

The original characterisation of B7-33 reported that the peptide prevented or reversed organ fibrosis and dysfunction in several preclinical models involving heart and lung disease. The researchers linked these effects to selective RXFP1 signalling and downstream ERK/MMP-2 activity.

These findings support continued laboratory investigation of B7-33 in relation to extracellular-matrix regulation and organ fibrosis.

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B7-33 and Cardioprotective Research

Cardioprotection refers broadly to mechanisms that help preserve cardiac tissue or function during and following injury.

B7-33 has been studied as a potential research tool for investigating cardioprotective signalling associated with the relaxin system. Experimental studies have examined outcomes including infarct size, cardiac contractile function and fibrosis following cardiovascular injury.

A 2023 experimental study reported that B7-33 maintained cardioprotective effects in a model of cardiomyopathy and reduced left-ventricular fibrosis more rapidly than perindopril in that experimental setting.

Such findings are relevant to mechanistic cardiovascular research but should not be interpreted as evidence that B7-33 is an established cardiovascular therapy.

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B7-33 and Cardiomyopathy Research

Cardiomyopathy encompasses a range of disorders affecting the structure and function of cardiac muscle. Chronic remodelling and fibrosis can contribute to deterioration in cardiac performance.

Research published in 2023 investigated B7-33 in an experimental model of cardiomyopathy. The study reported preservation of cardioprotective effects and a more rapid reduction in left-ventricular fibrosis compared with the comparator used in the study.

This research provides another experimental framework for studying how selective relaxin-receptor signalling may influence cardiac remodelling.

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B7-33 Compared With H2 Relaxin

Characteristic	B7-33	H2 Relaxin
Structure	Single-chain synthetic peptide	Complex two-chain peptide hormone
Structural basis	Relaxin-2 B-chain analogue	Full-length human relaxin-2
Primary receptor of interest	RXFP1	RXFP1
Signalling profile	Preferential ERK-related signalling in research models	Broader RXFP1 signalling including cAMP and ERK pathways
Research interest	Selective receptor signalling and anti-fibrotic mechanisms	Vascular, reproductive, tissue-remodelling and other physiological processes
Research format	Synthetic peptide analogue	Endogenous peptide hormone

B7-33 is therefore not simply a smaller version of full-length relaxin. Its design was intended to produce a distinct and more selective signalling profile, making it useful for structure-function and receptor-signalling research.

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B7-33 and Relaxin Family Receptors

The relaxin peptide family interacts with several receptor types known as RXFP1, RXFP2, RXFP3 and RXFP4. These receptors have different ligand specificities and biological functions.

RXFP1 is particularly important for B7-33 research because B7-33 was developed as a selective agonist of this receptor.

Studies of relaxin-family peptides have demonstrated that receptor selectivity is an important determinant of biological activity. Researchers continue to investigate how structural modifications affect receptor binding, activation and downstream signalling.

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B7-33 and RXFP1 Selectivity

The concept of functional selectivity is central to B7-33 research. A ligand can interact with a receptor while preferentially activating particular intracellular signalling pathways.

B7-33 was reported to preferentially activate ERK signalling through RXFP1 rather than producing the same cAMP response associated with full-length H2 relaxin. This makes the peptide an important experimental model for studying biased or functionally selective GPCR signalling.

Understanding these signalling differences can help researchers investigate which intracellular pathways are associated with particular biological outcomes.

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B7-33 and MMP-2 Research

Matrix metalloproteinase-2 (MMP-2) is an extracellular enzyme involved in the turnover of components of the extracellular matrix.

Research into B7-33 has linked selective RXFP1 activation with signalling that increases MMP-2 activity. This proposed mechanism is particularly relevant to anti-fibrotic research because excessive extracellular-matrix accumulation is a defining feature of many fibrotic conditions.

The relationship between RXFP1, ERK1/2 and MMP-2 therefore provides an important molecular framework for investigating how B7-33 may influence pathological tissue remodelling in experimental models.

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B7-33 and Extracellular-Matrix Research

The extracellular matrix provides structural support for cells and tissues and also participates in cellular signalling. Its composition is continuously regulated through synthesis and degradation.

When matrix production exceeds degradation, excessive accumulation can occur and contribute to fibrosis. Because B7-33 research has identified pathways involving MMP-2 and matrix remodelling, the peptide is of interest to researchers studying extracellular-matrix homeostasis.

Laboratory investigation of B7-33 can therefore provide insight into the relationship between receptor signalling and structural changes in tissues.

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B7-33 Research Applications

B7-33 may be relevant to controlled laboratory research involving:

• RXFP1 receptor research: Investigation of relaxin receptor activation and signalling.
• GPCR research: Study of functional selectivity and receptor-mediated intracellular pathways.
• Fibrosis research: Investigation of mechanisms involved in pathological extracellular-matrix accumulation.
• Cardiovascular research: Study of cardiac injury, remodelling and tissue responses.
• Vascular biology: Investigation of vascular signalling and vasoprotective mechanisms.
• Cardiac remodelling: Research into fibrosis and structural changes following cardiac injury.
• Pulmonary research: Investigation of fibrotic changes in experimental lung models.
• Extracellular-matrix research: Study of collagen turnover and matrix-remodelling pathways.
• MMP research: Investigation of matrix metalloproteinase activity.
• Relaxin structure-function studies: Comparison of peptide analogues with full-length relaxin.
• Signal-transduction research: Investigation of ERK1/2 and cAMP signalling.
• Peptide drug-discovery research: Evaluation of smaller peptide analogues designed to retain selected receptor activity.

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B7-33 (6mg) Research Specifications

Specification	Details
Product	B7-33
Quantity	6mg
Compound class	Relaxin analogue
Structural basis	Human H2 relaxin B-chain
Structure	Single-chain peptide
Primary receptor	RXFP1
Research signalling pathway	ERK1/2 and related RXFP1 signalling
Additional signalling research	MMP-2 and extracellular-matrix remodelling
Product form	Lyophilised powder
Stated purity	>99%
Research focus	Receptor signalling, fibrosis, vascular and cardiovascular biology
Intended application	Laboratory research

Product-specific format and purity information are based on the referenced Core Peptides listing.

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Why Researchers Study B7-33

B7-33 is scientifically interesting because it demonstrates how a complex peptide hormone can be reduced to a smaller molecular structure while retaining selected receptor activity.

Its functionally selective interaction with RXFP1 provides researchers with an opportunity to investigate the relationship between receptor activation and downstream signalling. In particular, the peptide has been studied for its ability to favour ERK-associated signalling and mechanisms involving extracellular-matrix remodelling.

The resulting research profile has extended into several fields, including fibrosis, vascular biology and cardiovascular remodelling.

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B7-33 and Preclinical Fibrosis Studies

One of the most important areas of published B7-33 research involves experimental models of organ fibrosis.

The original characterisation study reported that B7-33 prevented or reversed fibrosis and organ dysfunction in three preclinical rodent models involving heart or lung disease. The researchers linked these effects to selective RXFP1 activation, ERK1/2 signalling and MMP-2 activity.

These findings established an important foundation for subsequent research examining B7-33 in cardiovascular and tissue-remodelling models.

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B7-33 in Experimental Cardiovascular Models

Subsequent studies have expanded research into the cardiovascular effects of B7-33. Experimental work has investigated myocardial infarction, ischaemia-reperfusion injury, cardiomyopathy and cardiac fibrosis.

In a mouse myocardial ischaemia-reperfusion model, B7-33 was associated with reduced infarct size and preservation of cardiac contractile function compared with vehicle treatment.

More recent experimental work has examined B7-33 in cardiomyopathy and reported preservation of cardioprotective effects alongside reductions in left-ventricular fibrosis.

These findings demonstrate the continuing interest in B7-33 as a research tool for investigating cardiac remodelling and tissue-protective signalling.

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B7-33 and Vascular Protection Research

Relaxin-2 has established research interest in vascular biology, particularly because of its vasodilatory and vasoprotective properties. B7-33 was developed in part to investigate whether selected activities of relaxin could be reproduced using a smaller and more selective peptide.

Experimental research has reported that B7-33 can reproduce several vasoprotective effects of human relaxin-2 in animal models. This provides an additional research pathway for investigating RXFP1-mediated vascular signalling.

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Frequently Asked Questions About B7-33 (6mg)

What is B7-33?

B7-33 is a synthetic single-chain peptide analogue derived from the B-chain of human H2 relaxin. It is primarily studied as a selective agonist of the RXFP1 receptor.

What is B7-33 derived from?

B7-33 is derived from the B-chain region of human H2 relaxin, also known as relaxin-2. Its simplified structure was developed to retain selected relaxin-like receptor activity.

What receptor does B7-33 target?

B7-33 has been characterised as a functionally selective agonist of RXFP1, the principal receptor associated with H2 relaxin signalling.

What is B7-33 studied for?

Research has investigated B7-33 in relation to RXFP1 signalling, fibrosis, extracellular-matrix remodelling, vascular biology, cardiac injury and cardiovascular remodelling.

Is B7-33 the same as relaxin?

No. B7-33 is a synthetic, simplified analogue based on the B-chain of H2 relaxin. Full-length H2 relaxin has a substantially more complex two-chain structure.

What makes B7-33 different from H2 relaxin?

B7-33 has been described as a functionally selective RXFP1 agonist that preferentially activates ERK-related signalling in experimental systems, whereas full-length H2 relaxin activates a broader range of signalling pathways.

Has B7-33 been studied for fibrosis?

Yes. Preclinical research has investigated B7-33 in models of cardiac and pulmonary fibrosis, with studies reporting anti-fibrotic effects in experimental settings.

Has B7-33 been studied in cardiovascular research?

Yes. Experimental studies have examined B7-33 following myocardial ischaemia-reperfusion injury and in models of cardiomyopathy and cardiac fibrosis.

What is RXFP1?

RXFP1 is a G protein-coupled receptor belonging to the relaxin family of peptide receptors. It is an important receptor for H2 relaxin and the principal receptor investigated in B7-33 research.

What is MMP-2?

MMP-2, or matrix metalloproteinase-2, is an extracellular enzyme involved in the breakdown and remodelling of components of the extracellular matrix. B7-33 research has investigated its role in the peptide’s proposed anti-fibrotic signalling mechanism.

What does the 6mg designation mean?

The 6mg designation refers to the quantity of B7-33 in the referenced research product. It is a product specification and should not be interpreted as a recommended human dose.

What form is B7-33 (6mg) supplied in?

The referenced product listing identifies B7-33 (6mg) as a lyophilised powder with a stated purity of greater than 99%.

Is B7-33 an approved medicine?

B7-33 should be regarded as an experimental research peptide. Preclinical findings should not be presented as proof of clinical efficacy, and research use should be distinguished from regulatory approval.

Can results from animal studies be applied directly to humans?

No. Animal studies are valuable for investigating mechanisms and generating hypotheses, but differences between experimental models and humans mean that findings cannot automatically be translated into clinical outcomes.

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Research-Use Disclaimer

B7-33 (6mg) is intended for laboratory and research applications only. It should not be marketed or represented as an approved medicine, dietary supplement or established treatment for fibrosis, cardiovascular disease, myocardial injury, vascular disorders or any other medical condition.

The scientific literature surrounding B7-33 includes cellular experiments and preclinical animal studies. Such findings provide useful information about molecular mechanisms but do not establish clinical effectiveness or safety in humans.

This product description does not provide dosing, administration or treatment instructions. Qualified researchers should consult appropriate scientific literature, product documentation, analytical data, institutional laboratory procedures and applicable regulations before conducting experiments involving B7-33.

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B7-33 (6mg) – Research Summary

B7-33 (6mg) is a synthetic, single-chain analogue derived from the B-chain of human H2 relaxin. It was developed as a simplified relaxin mimetic and has been characterised as a functionally selective agonist of RXFP1.

Its research profile is particularly associated with selective ERK1/2 signalling, extracellular-matrix remodelling and anti-fibrotic mechanisms. Experimental studies have investigated B7-33 in models of cardiac and pulmonary fibrosis, vascular biology, myocardial ischaemia-reperfusion injury and cardiomyopathy.

The 6mg product is supplied as a lyophilised powder, with the referenced supplier listing reporting a stated purity above 99%.

For appropriately equipped laboratories, B7-33 (6mg) provides a specialised research peptide for investigating relaxin-receptor signalling, functional selectivity, fibrosis, vascular responses and cardiovascular tissue remodelling.