Streptavidin Beads are stable, uniform, non-porous spheres bound with highly active streptavidin. They are RNase and DNase free for direct addition to cell or tissue lysates. The one-micron diameter beads bind 10 pmol biotinylated PNA-analog probe per 1 ul of beads and are supplied at ~1% solids in 50 mM Tris, pH 8, 150 mM NaCl, 0.05% sodium azide and 0.1% stabilizing detergent.