{"id":71510,"date":"2026-05-20T10:35:00","date_gmt":"2026-05-20T10:35:00","guid":{"rendered":"https:\/\/medsbase.com\/b7-33\/"},"modified":"2026-05-21T07:14:08","modified_gmt":"2026-05-21T07:14:08","slug":"b7-33","status":"publish","type":"product","link":"https:\/\/medsbase.com\/nl\/b7-33\/","title":{"rendered":"B7-33 (Biased RXFP1 Relaxin B-Chain Analogue)"},"content":{"rendered":"

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Quick Answer \u2014 What is B7-33?<\/h3>\n

B7-33<\/strong> is a synthetic 33-amino-acid single-chain relaxin-B-chain peptide analogue<\/strong> developed by Hossain, Howe and colleagues at the Florey Institute (Melbourne, Australia) and published in Nature Communications<\/em> (2017). Where native relaxin-2 (the canonical fibrosis-treating hormone, clinically Serelaxin) is a two-chain disulfide-linked A\/B-chain peptide that activates both RXFP1 (anti-fibrotic) and RXFP2 (pro-cancer-cell-survival) receptors, B7-33 is a biased RXFP1 agonist<\/strong> \u2014 single-chain B-only design that selectively engages RXFP1’s anti-fibrotic signalling (ERK1\/2 pathway \u2192 MMP-2 upregulation \u2192 ECM degradation) while avoiding RXFP1’s pro-cancer cAMP signalling that contributed to Serelaxin’s discontinuation. Published research applications: heart failure, liver \/ kidney \/ lung \/ cardiac fibrosis, pre-eclampsia. For laboratory research use only.<\/em><\/p>\n<\/div>\n

Wat u krijgt bij MedsBase:<\/strong> Lyophilized \u226599% HPLC-verified B7-33 \u00b7 COA available on request \u00b7 Discreet temperature-stable packaging \u00b7 Worldwide research-supply courier \u00b7 1,400+ verified klantbeoordelingen<\/a><\/div>\n

\ud83d\udce6 Elke bestelling is gedekt door onze Reshipment Assurance Policy<\/strong><\/a> \u2014 als uw pakket niet binnen 20 werkdagen arriveert, sturen wij het opnieuw.<\/p>\n\n\n\n\n\n\n\n\n\n\n\n\n
Specificatie<\/th>\nDetail<\/th>\n<\/tr>\n<\/thead>\n
Compound Class<\/strong><\/td>\nSynthetic 33-aa single-chain relaxin-B-chain analogue; biased RXFP1 receptor agonist (anti-fibrotic ERK pathway, with reduced cAMP pro-survival signalling)<\/td>\n<\/tr>\n
Chemical Name<\/strong><\/td>\nB7-33 (relaxin B-chain 7-33 analogue with stabilising modifications; Hossain et al. 2017 Nat Commun)<\/td>\n<\/tr>\n
CAS-nummer<\/strong><\/td>\nResearch-grade peptide \u2014 no widely-registered single CAS; identification by published sequence and supplier COA<\/td>\n<\/tr>\n
Molecuulformule<\/strong><\/td>\nSingle-chain 33-residue B-chain analogue \u2014 sequence-derived approximate MF C164<\/sub>H252<\/sub>N50<\/sub>O45<\/sub>S2<\/sub>; published MW ~3,728 Da (Hossain & Bathgate 2015, J Med Chem).<\/td>\n<\/tr>\n
Sequence Length \/ MW<\/strong><\/td>\n33 amino acids derived from H2-relaxin B-chain with N- and C-terminal modifications for solubility \/ stability; MW ~3,800 Da<\/td>\n<\/tr>\n
Werkingsmechanisme<\/strong><\/td>\nBiased RXFP1 agonist<\/strong>. Selectively activates ERK1\/2 \u2192 MMP-2 \/ MMP-9 upregulation \u2192 collagen-degradation \/ extracellular-matrix-remodelling pathway (the anti-fibrotic arm of RXFP1 signalling) while showing reduced engagement of cAMP-mediated RXFP1 signalling (the pathway implicated in Serelaxin’s adverse cardiac event signal and the pro-cancer-cell-survival effect that complicated relaxin clinical development).<\/td>\n<\/tr>\n
Form \/ Purity \/ Storage<\/strong><\/td>\nLyophilized white-to-off-white powder, \u226599% HPLC. Store 2\u20138 \u00b0C short-term, \u221220 \u00b0C long-term (\u226536 months). Reconstituted: 2\u20138 \u00b0C, use within 30 days.<\/td>\n<\/tr>\n
Onderzoeksgebruik<\/strong><\/td>\nFor laboratory research use only. Not on the WADA Prohibited List. Preclinical research compound.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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Mechanism of Action \u2014 Biased RXFP1 Agonism (ERK without cAMP)<\/h2>\n

B7-33 was designed by the Hossain \/ Howe \/ Bathgate group at the Florey Institute as an answer to the “Serelaxin problem”. Serelaxin (recombinant human relaxin-2) had completed Phase III trials for acute heart failure but failed to gain FDA approval \u2014 partly because of mixed cardiovascular safety signals attributed to RXFP1’s dual signalling (anti-fibrotic ERK pathway helpful; cAMP pathway potentially pro-arrhythmic and pro-cancer-cell-survival).<\/p>\n

B7-33’s design hypothesis: the relaxin B-chain alone<\/strong> (the chain that mediates RXFP1 binding) can be engineered into a stable single-chain peptide that activates only the ERK1\/2 \/ MMP-upregulation anti-fibrotic arm of RXFP1 signalling while skipping the cAMP-mediated pro-cancer\/pro-arrhythmic arm. The published 2017 Nature Communications paper confirmed this: B7-33 produces measurable RXFP1-ERK1\/2 activation but minimal cAMP elevation \u2014 defined biased agonism. In published mouse models of cardiac fibrosis, kidney fibrosis, and pre-eclampsia, B7-33 produced equivalent or greater anti-fibrotic efficacy compared with native relaxin without the cAMP-mediated complications.<\/p>\n

Gepubliceerde onderzoeksapplicaties<\/h2>\n