Our streptavidin, Alexa Fluor 405 conjugate is a bright, photostable probe with excitation/emission maxima of 402 and 421 nm. Streptavidin is a nonglycosylated biotin-binding protein that is isolated from bacteria and has a near-neutral isoelectric point. It is widely used to detect biotinylated probes, because it reportedly exhibits less nonspecific binding than does the glycosylated, biotin-binding protein, avidin. View a selection guide for all Alexa Fluor™ streptavidin and avidin conjugates.