• High quality, ready-to-use conjugates
• Suited for fluorescence microscopy, flow cytometry, fluorescent in situ hybridization (FISH) & fluorescence immunoassay (FIA)

Avidin and streptavidin have a very strong affinity for biotin with a dissociation constant of approximately 10-15 mol/l. This is the highest known affinity between any protein and its ligand. Extensive chemical modifications have little effect on this affinity.
Avidin is a tetrameric glycoprotein with a combined mass of approximately 67 kDa. Due to its carbohydrate content and basic pI, avidin shows relatively high nonspecific binding.
Streptavidin is a tetrameric 53 kDa protein. Since it lacks any carbohydrate modification and has a near-neutral pH, it has the advantage of much lower nonspecific binding than avidin. On the other hand, streptavidin is less water soluble than avidin.

Ready-to-use avidin, streptavidin, and biotin conjugates of R-Phycoerythrin, B-Phycoerythrin, and Allophycocyanin are available. These ready-to-use conjugates are very useful second-step reagents for staining with biotinylated or streptavidin-coupled antibodies and can be used in (strept)avidin/biotin-labeling systems for flow cytometry, fluorescent immunoassays, immunohistochemistry, and immunofluorescence microscopy.

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