Question

An enzyme sample contains 24 mg protein/mL. Of this sample, 20
microliters in a standard incubation volume of 0.1 mL catalyzed the
incorporation of glucose into glcogen at a rate of 1.6 nmol/min. Calculate the
velocity of the reaction in terms of the following:

A)micromoles/minute
B)micromoles/liter/minute
C)micromoles/miligrams of protein/minute
D)Units/milliliter
E)Units/miligrams of protein


Of this sample, 50 mL were fractionated by ammonium sulfate
precipitation. The fraction precipitating between 30 and 50% saturation was
redissolved in a total volume of 10 mL and dialyzed. The solution after
dialysis had 12 mL and contained 30 mg protein/mL. Of the purified fraction,
20 microliters catalyzed the reaction rate of 5.9 nmol/min under the
standard assay conditions. calculate the following:

A. The recovery of enzyme after the ammonium sulfate step.
B. The fold purification after the ammonium sulfate step.

note: for recovery: divide total units of he sample by the total units of the crude homogenate and multiply by 100.
for fold purification: it is the ratio of the specific activity of a given fraction divided by the specific activity of the crude homogenate.

Answer 1

Note: a Unit is ((ΔA/Δmin)/(6220 M -1 cm -1)) X 106 μM/M X 3 X 10-3 L