Dilution of Streptavidin Conjugates

Working Dilution of Streptavidin conjugates from Jackson Immuno is now standardized to a working concentration of 2 µg/ml, which is the upper end of Jackson's recommended 1 - 2 µg/ml.

Calculations are based on:

1. Each vial of streptavidin contains 1.0 mg, regardless of conjugate
2. Every conjugate is a different concentration (HRP at 1.0, Cy 2 at 1.2 and Cy 3/Cy 5 at 1.8 mg/ml)
3. Each concentration is reconstituted with a different volume of DI (1 ml, 950 µl and 650 µl, for HRP, Cy2 and Cy 3/Cy 5, respectively)

Calculations for 2 µg/ml:

 HRP⦁Streptavidin (1:500)

HRP⦁Streptavidin comes as 1.0 mg, rehydrated with 1.0 ml DI = 1 µg/µl. Therefore 2 µl's/ml are needed for a working concentration of 2 µg/ml. 2 µl's/ml = 1:500, or 20 µl per aliquot makes 10 ml at 1:500. 1 ml theoretically makes 50 aliquots at 20 µl per aliquot

 Cy 2⦁Streptavidin (1:526)

 Cy 2⦁Streptavidin comes as 1.0 mg, at a concentration of 1.2 mg/ml, and is rehydrated with 950 µl DI. 1 mg in 950 µl = 1.05 µg/µl and 2 µg = 1.9 µl. Therefore 1.9 µl's/ml are needed for a working concentration of 2 µg/ml, which would be 19 µl in 10 ml, which is a dilution of 1:526. Note that again 950 µl theoretically makes 50 aliquots at 19 µl per aliquot.

 Cy 3⦁Streptavidin (1:769)

 Cy 3⦁Streptavidin comes as 1.0 mg, at a concentration of 1.8 mg/ml, and is rehydrated with 650 µl DI. 1 mg in 650 µl = 1.54 µg/µl and 2 µg = 1.3 µl. Therefore 1.3 µl's/ml are needed for a working concentration of 2 µg/ml or 13 µl per aliquot for 10 ml, which is a final dilution of 1:769. Here, too, 650 µl theoretically makes 50 aliquots at 13 µl per aliquot

 Cy 5⦁Streptavidin and Alexa 647⦁Streptavidin (1:769)

 Cy 5⦁Streptavidin also comes as 1.0 mg, at a concentration of 1.8 mg/ml, and is rehydrated with 650 µl DI. 1 mg in 650 µl = 1.54 µg/µl and 2 µg = 1.3 µl. Therefore 1.3 µl's/ml are needed for a working concentration of 2 µg/ml or 13 µl per aliquot for 10 ml, which is a final dilution of 1:769. Here, too, 650 µl theoretically makes 50 aliquots at 13 µl per aliquot