Biotin peptide is a molecule that has been labeled with a biotin tag, usually attached to the N-terminus or C-terminus. The N-terminal biotinylation can be performed directly to the primary amino group of the peptide, while the C-terminal biotinylation is normally carried out to the e-amino group of an extra lysine.
Peptide biotinylation is a commonly used method of enhancing specificity in immunodetection studies, as well as to connect peptides to microtitration plates coated with avidin proteins for use in immunoassays such as a peptide pulldown test. Creative Peptides routinely synthesizes a variety of peptides with biotin tags, as part of our peptide production service.
Using biotin to label peptides is an effective strategy that can be applied either during Fmoc solid phase synthesis or post synthesis, with a variety of spacer arm options available. A hydrophobic straight chain spacer such as the 6-carbon e-aminohexanoic (Ahx) is often applied to biotinylated peptides, while a hydrophilic tetrapeptide such as -SGSG- can also be used.
Iminobiotin is another effective analog of biotin and has been found to have moderated interaction with avidin or streptavidin binding sites. Its structure has a 2-imino-imidazole ring that causes mild dissociation of the (strept)avidin binding site, making it a valuable addition to avidin/biotin labeling reagents.
Avidin-biotin conjugates are useful for many applications in nonradioactive methods of purification, detection, immobilization, labeling and drug targeting systems. The extraordinary affinity of avidin for biotin (Ka=1015M-1) makes it one of the strongest non-covalent interactions known, allowing biotin-containing molecules in a complex mixture to be discretely bound with avidin.