Streptavidin from Streptomyces avidinii, essentially salt-free, lyophilized powder, ≥13 units/mg protein
Streptavidin from Streptomyces avidinii, affinity purified, lyophilized from 10 mM potassium phosphate, ≥13 U/mg protein
Streptavidin from Streptomyces avidinii, recombinant, expressed in E. coli, lyophilized powder