Calculating protein yields and recovery

Protein extraction efficiency is an important measure of the effectiveness of protein separation. Calculating the amount of protein recovered is, therefore, important to assess the efficiency of the technique used. Protein recovery may be defined as the ratio of the total mass of protein recovered in the dried extract divided by the total mass of protein present in the starting material as shown in Equation 3.1 below  

the closer the mass of the protein extracted to the original amount present in the starting material, the more efficient is the protein recovery. 

Mass of protein extracted (g) Total mass of starting material (g) 

Another frequently used measure of protein extraction efficiency is protein purity, defined as the concentration of protein in the final extract as measured by the Kjedhal or Dumas methods or a method analyzing for true protein (e.g., Lowry, Bradford or BCA methods). Protein purity may, therefore, be defined as the ratio of the mass of protein in the dried recovered extract divided by the total mass of the dried extract as shown in Equation 3.3  

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