Biotin-Bradykinin is an N-terminally biotinylated derivative of the nine-residue Bradykinin sequence. The construct combines RPPGFSPFR with a biotin affinity handle for streptavidin-based capture, immobilization and ligand-interaction studies.

Unlike native Bradykinin, this material is designed primarily as an analytical and biochemical probe. The added biotin group enables assay formats that are not possible with an unlabeled peptide while also introducing a structural modification that should be considered when receptor activity is quantified.

Product Information

A Tagged Kinin for Affinity-Based Experiments

Biotin binds streptavidin and avidin-family proteins with very high affinity, allowing a peptide ligand to be incorporated into immobilized or detection-oriented assay formats.

Biotin-Bradykinin can therefore support streptavidin-coated surfaces, pull-down workflows, ligand capture, receptor-interaction experiments and development of biochemical assays in which unlabeled Bradykinin would be difficult to detect directly.

The C-Terminal Arg Remains Intact

The construct retains the complete Bradykinin sequence through its C-terminal Arg9. This is important because removal of Arg9 generates des-Arg9-Bradykinin and changes kinin-receptor pharmacology toward the B1 receptor.

N-terminal biotinylation does not convert the sequence into a B1-selective kinin. When receptor pharmacology is the endpoint, the most appropriate reference remains intact unlabeled Bradykinin and a defined B2 receptor system.

Biotinylation Can Affect Quantitative Pharmacology

The biotin tag increases molecular size and changes the chemical environment at the peptide N-terminus. These changes can influence ligand affinity, receptor activation, surface orientation or steric accessibility.

We recommend measuring the activity of the labeled construct directly rather than assuming that its EC₅₀, binding affinity or signaling kinetics are identical to native Bradykinin.

Soluble and Immobilized Ligand Assays

Biotin-Bradykinin can be studied in solution or captured on streptavidin-containing surfaces. These two experimental configurations should be interpreted separately.

Surface immobilization can create orientation effects, local ligand-density effects or multivalent interactions that are absent when the peptide is freely diffusible. Appropriate unlabeled and streptavidin-only controls can help distinguish receptor-specific interaction from assay-platform effects.

Analytical Confirmation

For a conjugated peptide, chromatographic purity alone does not confirm the position or completeness of labeling. Molecular-mass analysis is useful for verifying successful biotin incorporation and detecting unmodified peptide or synthesis-related species.

Our Peptide Quality Control capabilities support analytical HPLC and mass spectrometry according to project requirements.

Research Applications

Biotin-Bradykinin can support ligand–receptor interaction studies, streptavidin capture assays, immobilized peptide experiments, assay development and comparative studies of labeled versus native kinins.

Alternative biotin positions, spacer-containing constructs and other labeled Bradykinin analogs can be evaluated through Chemical Peptide Synthesis.

Frequently Asked Questions

Where is the biotin group attached?

The listed construct contains an N-terminal biotin group attached before Arg1 of the Bradykinin sequence.

Does Biotin-Bradykinin selectively represent B1 receptor signaling?

No. The peptide retains the intact RPPGFSPFR sequence associated primarily with B2 receptor pharmacology. B1 receptor agonists typically lack the C-terminal Arg.

Can labeled and unlabeled Bradykinin be assumed to have identical potency?

No. The added biotin group can alter receptor interaction or assay behavior, so quantitative activity should be measured experimentally.

Research Use Only.