The Steptavidin is produced by fermentation of S. avidinii in a minimal medium.
The protein has a structure with four identical subunits, each containing a binding site for biotin. It is stable over a wide range of pH and decomposes only in the presence of SDS at temperatures above
60 °C. Steptavidin conjugated with an enzyme, i.e. Horseradish Peroxidase or Alkaline Phosphatase or a fluorochrome may be used to visualize biotin labelled antibodies. Compared to Avidin, Steptavidin has a lower non-specific binding.