# Convert DNase units to weight - 2mg/ml from a 2U/ml solution (Sep/16/2004 )

hello guys!

I need to prepare a 2 mg/mL DNAase solution. the DNAase stock has a concentration of 2U/ml. how can i make a 2mg/ml from a 2U/ml solution? this is quite hard to figure out .

hope very much for replies!

thanks for helping!

-justwonder-

It hard to convert units to weight unless the vendor provides such information. Some vendors say one mg dry weigt of DNase I has >2,000 Kunitz units. Qiagen explicitily says that one mg = 2500 Kunitz units. If this is given, you can estimate the weight. However this number may not be applied to DNase from another vendor since they may have different activity.

-labrat-

hello labrat!

thanks for your helping, but still i can't figure out how to make a 2mg/ml from a 2U/ml, if for instance as your vendor said; 1 mg= 2500 Kunitz units. hope that you can show me the calculation. by the way what is Kunitz units? i am new about this, so hope that you can help me out!

thanks alot!

-justwonder-

One Kunitz unit is defined as the amount of DNase I that causes an increase in A260 of 0.001 per minute per milliliter at 25°C, pH 5.0, with highly polymerized DNA as the substrate
One unit is the amount of the enzyme required to degrade 1 mg of calf thymus DNA in 10 minutes at 37°C completely. (1.5 units = 1 Kunitz unit)

-Vickym-