Question

After a protein preparation you ended with 350uL of 25mg/mL protein. What is the total yield of your protein? If molecular weight of protein is 35,000 Da what is the molarity (M) of the protein at concentration 25mg/mL?

Answer 1

total yield = volume x concentration

given

volume = 350 ul

volume = 350 x 10-6 L

also

concentration = 25 mg / ml

cocentration = 25 mg / 10-3 L

so

totall yield = 350 x 10-6 x 25 / 10-3

total yield = 8.75 mg

so

the total yield of protein is 8.75 mg

now

we know that

moles = mass / molar mass

so

moles of protein = 8.75 x 10-3 / 35000

moles of protein = 2.5 x 10-7

now

we know that

molarity = moles / volume (L)

so

molarity = 2.5 x 10-7 / 350 x 10-6

molarity = 7.143 x 10-4

so

the molarity of the protein is 7.143 x 10-4 M