Question

You are given 300 µl of LDH and are told that it has a total activity of 25 U. The concentration of protein in this sample is 10 mg/ml. Calculate this sample’s enzyme concentration in units of U/ml. Calculate also the specific activity of this sample in units of U/mg.

Answer 1

The sample's enzyme concentration = 25 U/300 µL

= 25 U/(300*10^-3 mL)

= 83.33 U/mL

Note: 1 µL = 10^-6 L, 1 L = 10³ mL

Now, the sample's enzyme concentration = (83.33 U/mL)/(10 mg/mL)

= 8.333 U/mg