Question

1. The molecular mass of a protein is 50000 Da. (A) What is the mg/mL concentration of a 40-µM solution of the protein? (B) What is the percentage concentration of this solution?

Answer 1

given

molecular mass of protein= 50000 Da

= 50000 gram/mole

(A) Molarity (M) = {amount of solute (gram)/ mw of solute (gram/mole) }/ 1L

40 X 10^-6 mole/ Litre= {amount of protein (gram)/ 50000 gram/mole) }/ 1L 1 Micromole =  10^-6 mole

amount of protein = 0.20 gram/ Litre

=  0.20 X10^-3 gram/ mL

(B)

mass / volume percent= mass of solute (gram)/volume of solution (mL) X 100

= 0.20 X10^-3 gram/ mL X100

=0.02 % Answer