This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
Protein is purified using ammonium sulfate by 
Select and explain. 
A. Salting out, B. Ion exchange chromatography, C. Mass chromatography, D. Molecular size exclusion
A: Salting out
Answer: A: Salting out 
Explanation: The process of protein precipitation by the addition of neutral salts such as Ammonium sulfate or Sodium sulfate is called salting out. This phenomenon is explained on the basis of dehydration of protein molecules by salts. This increased protein_protein interaction,resulting in molecular aggregation and precipitation.TSalting out procedure is conveniently used for separating serum albumins from globulins