One method of isolating polypeptides and proteins from aqueous extracts is freeze drying. The aqueous solution of the polypeptide or protein is frozen. What procedure can be used to remove the water from the frozen sample?

Answer: Sublimation under reduced pressure

Explanation:

Sublimation can be defined as a process which can be used to remove solvent from the solution so that it can be pure.

The extracted protein is cooled down in liquid nitrogen in order to avoid deleterious effect. Water from the frozen protein is removed by the process of sublimation under reduced pressure.

During this procedure the water droplets are removed and proteins is stored for future use in the laboratory.