B7-33 - Research Grade Peptide

B7-33 – Research-Grade 27-Residue Single-Chain Peptide

For research purposes only. This product is supplied exclusively for scientific laboratory research and analytical purposes. It is not intended for human or animal use, consumption, clinical use or therapeutic application. It must not be used in any way that contravenes applicable laws or the requirements of the Medicines and Healthcare products Regulatory Agency.

• Research-grade, sequence-defined B7-33 single-chain peptide with batch documentation available where supplied
• Defined 27-residue sequence derived from positions 7–33 of the extended human relaxin-2 B-chain
• Contains serine substitutions corresponding to the native B-chain cysteine residues at positions 11 and 23
• C-terminally amidated linear peptide containing no cysteine residues or disulphide bonds
• Supplied as measured dry or lyophilised laboratory material in sealed flip-top headspace vials
• Batch identity, chromatographic purity, molecular mass, peptide content and analytical specifications stated in the applicable Certificate of Analysis
• Handled and supplied exclusively as a research-use laboratory material

B7-33 is a synthetic, single-chain peptide derived from the B-chain of human relaxin-2. The defined research peptide is more precisely described as B7-33 C11.23S because the cysteine residues corresponding to positions 11 and 23 of the native human relaxin-2 B-chain have been replaced by serine. The supplied structure contains a free N-terminal valine and a C-terminal leucinamide.

Each vial contains measured laboratory material prepared to support controlled scientific handling, storage, analytical method development, chromatographic assessment, mass-spectrometry evaluation and peptide characterisation. The stated nominal quantity refers to the declared B7-33 peptide content of one vial, subject to the applicable batch documentation and stated assay basis.

Where laboratory dissolution is required, the solvent, buffer, concentration, mixing procedure and storage conditions stated in the applicable Certificate of Analysis, Safety Data Sheet or validated laboratory method should be followed. A universal bacteriostatic-water instruction should not be applied to every peptide batch, counter-ion form or laboratory preparation.

Research Scientific Ltd does not provide advice or recommendations concerning dosage, administration or use in humans or animals.

Chemical and Structural Information:

• Product Name: B7-33
• Preferred Technical Description: Modified B7-33 C11.23S human relaxin-2 B-chain analogue
• Alternative Scientific Designations: B7-33 C11.23S; modified B7-33; single-chain relaxin-2 B-chain analogue; H2 relaxin B-chain 7–33 C11.23S
• Material Classification: Synthetic sequence-defined linear peptide
• Sequence Length: 27 amino-acid residues
• Complete Peptide Sequence: H-Val-Ile-Lys-Leu-Ser-Gly-Arg-Glu-Leu-Val-Arg-Ala-Gln-Ile-Ala-Ile-Ser-Gly-Met-Ser-Thr-Trp-Ser-Lys-Arg-Ser-Leu-NH₂
• One-Letter Sequence: VIKLSGRELVRAQIAISGMSTWSKRSL-NH₂
• B-Chain Numbering: Corresponds to positions 7–33 of the extended human relaxin-2 B-chain
• Native B-Chain Cysteine Substitutions: Cys^B11→Ser and Cys^B23→Ser
• Positions Within the Isolated B7-33 Sequence: The substituted serine residues occur at positions 5 and 17 of the 27-residue peptide
• N-Terminal Structure: Free L-valine amino terminus
• C-Terminal Structure: C-terminal L-leucinamide
• Cyclic or Linear Structure: Linear single-chain peptide
• Cysteine Content: None
• Disulphide-Bond Content: None; both native relaxin-2 B-chain cysteine positions are occupied by serine in the defined B7-33 C11.23S structure
• Methionine Content: One methionine residue
• Sulphur Content: One sulphur atom contributed by the methionine residue
• CAS Number: 1818415-56-3
• PubChem Compound Identifier: CID 162662592
• Molecular Formula: C₁₃₁H₂₂₉N₄₁O₃₆S
• Average Molecular Weight: Approximately 2986.58 g/mol
• Approximate Molecular Size: 2.99 kDa
• Calculated Monoisotopic Mass: Approximately 2984.7070 Da
• Formula Basis: The molecular formula and molecular weight describe the uncountered, C-terminally amidated B7-33 C11.23S peptide without acetate, trifluoroacetate, residual water, solvents or formulation excipients
• Human Relaxin-2 Distinction: B7-33 is a single B-chain-derived peptide and is not chemically identical to the complete two-chain human relaxin-2 molecule
• Native B7-33 Distinction: The unmodified B7-33 sequence containing cysteine at the corresponding B11 and B23 positions is a different molecular structure from the C11.23S peptide described on this page
• N-Terminally Acetylated Analogue Distinction: Ac-B7-33 C11.23S contains an additional covalent N-terminal acetyl modification and is a separate molecular structure
• Physical Form: Dry powder or lyophilised laboratory material, as stated in the applicable batch Certificate of Analysis
• Appearance: White to off-white laboratory material where confirmed by the applicable batch documentation
• Chromatographic Purity: The applicable high-performance liquid chromatography result, analytical method and acceptance criterion should be stated in the batch Certificate of Analysis
• Purity Interpretation: Chromatographic area percentage represents relative chromatographic composition under the stated analytical conditions and does not, by itself, establish molecular identity or net peptide content
• Peptide-Content Specification: Net B7-33 peptide content should be distinguished from chromatographic purity and interpreted alongside counter-ion content, water content, residual solvents and formulation components
• Nominal Amount Basis: The applicable product specification should state whether the declared vial quantity is expressed as anhydrous parent-peptide equivalent or as total supplied salt-form or formulated material
• Sequence Confirmation: The complete 27-residue sequence should be confirmed using the applicable supplier, synthesis and batch records
• Substitution Confirmation: The two intended Cys-to-Ser substitutions should be supported by the sequence record and appropriate molecular-identity documentation
• C-Terminal Amidation Confirmation: Molecular-identity documentation should confirm the C-terminal leucinamide and distinguish it from the corresponding free carboxylic acid structure
• Mass-Spectrometry Confirmation: The observed molecular mass should be consistent with the complete, C-terminally amidated B7-33 C11.23S structure
• Chemical-Form Confirmation: The applicable Certificate of Analysis should identify whether the supplied material is the uncountered peptide, an acetate-containing form, a trifluoroacetate-containing form or another counter-ion presentation
• Counter-Ion Specification: Acetate, trifluoroacetate or another counter-ion may affect total supplied material mass and calculated net B7-33 peptide content
• Water-Content Specification: Residual water and hydration state may contribute to the total material mass and should be stated or controlled through the applicable batch specification
• Residual-Solvent Specification: Applicable residual solvents arising from synthesis, cleavage, purification, concentration and lyophilisation should be stated or controlled through the batch specification
• Methionine-Oxidation Control: Methionine sulfoxide and other oxidation products should be assessed or controlled where required by the applicable batch specification
• Related-Impurity Control: Deletion sequences, truncated peptides, incompletely amidated material, incompletely deprotected material, unmodified cysteine-containing sequences and other synthesis-related or process-related substances are separate quality attributes
• Dissolution Method: The appropriate solvent, buffer, concentration and mixing procedure should be selected using the exact chemical form, applicable batch documentation and validated laboratory method
• Bacterial Endotoxin Specification: The applicable bacterial endotoxin or lipopolysaccharide result, analytical method, reporting units, method-suitability controls and acceptance criterion should be stated in the batch Certificate of Analysis
• Sterility Distinction: A bacterial endotoxin or lipopolysaccharide result does not establish sterility. Sterility should only be claimed where supported by an appropriate validated sterility test and controlled filling process
• Analytical Interpretation: Molecular identity, complete sequence, substitution pattern, terminal amidation, chromatographic purity, net peptide content, counter-ion content, water content, residual solvents, oxidation products and bacterial endotoxin results are separate analytical measurements and should be interpreted together

✓ Batch documentation – Completed Certificate of Analysis documentation is provided where supplied for the applicable batch.
✓ Sequence documentation – The complete 27-residue VIKLSGRELVRAQIAISGMSTWSKRSL-NH₂ sequence should be recorded.
✓ Substitution documentation – The Cys^B11→Ser and Cys^B23→Ser substitutions should be supported by the applicable synthesis records.
✓ C-terminal modification documentation – C-terminal leucinamide should be confirmed and distinguished from the corresponding free-acid structure.
✓ Mass-spectrometry documentation – Molecular identity should be supported by analytical mass data consistent with the specified B7-33 structure.
✓ Chromatographic documentation – High-performance liquid chromatography purity should be reported separately from molecular identity and net peptide content.
✓ Peptide-content documentation – Net B7-33 content should be distinguished from total vial mass, residual water, counter-ions and formulation components.
✓ Chemical-form documentation – Acetate, trifluoroacetate or another counter-ion should be identified where present.
✓ Oxidation-control documentation – Methionine oxidation should be assessed or controlled where required by the applicable research specification.
✓ Bacterial endotoxin documentation – The method, reporting units, suitability controls, acceptance criterion and batch result should be recorded.
✓ Safety Data Sheet – Supplied to support appropriate laboratory handling, storage and regulatory compliance.
✓ Supplier documentation – Reviewed where supporting synthesis, purification and analytical records are supplied.
✓ Trackable laboratory delivery – Securely packaged and dispatched using transport controls appropriate to the applicable batch stability and storage specification.

For Research Use Only
This product is supplied strictly for scientific research, laboratory analysis and experimental work. It is not intended for human consumption, animal use, clinical use, diagnostic use or any form of therapeutic application.

B7-33 Product Overview

Our B7-33 research-grade single-chain peptide is supplied for controlled analytical method development, peptide identity assessment, high-performance liquid chromatography evaluation, liquid chromatography–mass spectrometry workflows, impurity profiling, reference-material comparison and other scientific laboratory investigations.

The PEP065 molecular identity comprises a defined 27-residue sequence derived from positions 7–33 of the extended human relaxin-2 B-chain. The cysteine residues corresponding to B-chain positions 11 and 23 are replaced by serine, producing the sequence VIKLSGRELVRAQIAISGMSTWSKRSL-NH₂.

The molecule has a free N-terminal valine and a C-terminal leucinamide. It contains no cysteine residues and therefore has no intramolecular or intermolecular disulphide bonds. Its single sulphur atom is contributed by the methionine residue within the sequence.

CAS number 1818415-56-3, molecular formula C₁₃₁H₂₂₉N₄₁O₃₆S and average molecular weight approximately 2986.58 g/mol describe the uncountered, C-terminally amidated B7-33 C11.23S molecule. Where the supplied material contains acetate, trifluoroacetate, residual water, solvents or formulation components, the applicable batch documentation should identify their contribution to the total supplied material mass.

B7-33 should not be confused with complete two-chain human relaxin-2, the cysteine-containing native B7-33 sequence, N-terminally acetylated B7-33 derivatives or shorter minimal-sequence analogues. Those materials have different molecular structures, molecular masses and analytical acceptance criteria.

Chromatographic purity should not automatically be interpreted as equivalent to total net B7-33 peptide content or proof of the complete sequence and terminal structure. Molecular identity should be assessed using the applicable combination of sequence documentation, high-performance liquid chromatography, mass spectrometry, peptide-content analysis and batch-production records.

A bacterial endotoxin or lipopolysaccharide result does not establish sterility, complete molecular identity, correct substitution pattern, terminal amidation or the absence of every peptide-related and process-related impurity.

For the majority of routine analytical method development, chromatographic assessment, mass-spectrometry comparison, impurity profiling, peptide characterisation and general laboratory work, the Regular B7-33 specification remains highly suitable. The premium black-and-gold ULTIMATE B7-33 option provides an additional preparative high-performance liquid chromatography purification stage and a more stringent bacterial endotoxin or lipopolysaccharide testing specification for projects requiring enhanced quality-control parameters.

View Certificate of Analysis

View Safety Data Sheet