DF = 1/250 x 1/2
Vt = Et
Vf = final concentration of lactase in the commercial preparation
DF = Vt / Vf
Vf = Vt / DF
Vf = Et / (1/250)(1/2)
Vf = Et x 500
The commercial preparation was first diluted by 1 - 250 to prepare the stock solution, and it was further diluted by 1 -2 by mixing with the substrate stock solution to perform the kinetics experiments.
Therefore, the dilution factor is done when you take whatever you initial volume was - in this case 1mL - and divide it by the new diluted volume - 0.1mL + 25mL. Then we get is 0.1/25.1, which is more easily solved as 1/250.
Since, this was a double dilution, 1mL of the initial dilution was diluted further with 1mL of substrate. So the second dilution factor will be 1/(1+1) = 1/2.
To learn more about kinetic experiments here
https://brainly.com/question/13004369
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