Biotin is a water-soluble member of the B-vitamin family with a molecular weight of 244 daltons. Biotin-labeled molecules can be purified or detected using streptavidin, NeutrAvidin or monomeric avidin. The biotin-streptavidin binding - taking place under physiological conditions - is one of the the strongest noncovalent biological interactions known and biotin is a very commonly used molecule for tagging of antibodies or other proteins. Thus, this fluorescent conjugates are making it easy to detect very sensitively various proteins which are widely used in bioanalytics.

Streptavidin is a bacterially derived, non-glycosylated, tetrameric 52,8 kDa biotin-binding protein with a near-neutral isoelectric point. It reportedly exhibits less nonspecific binding than avidin. However, streptavidin contains the tripeptide sequence Arg-Tyr-Asp (RYD) that apparently mimics the Arg-Gly-Asp (RGD) binding sequence of fibronectin.

We are offering biotin, avidin and streptavidin conjugates with all of our PromoFluor dyes (including our LSS dyes). 

In addition, we are also providing streptavidin and biotin conjugates with R-phycoerythrin (R-PE), B-phycoerythrin (B-PE), allophycocyanin (APC), cross-linked allophycocyanin (cl-APC) and fluorescein (FITC). More information