This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Isoelectric point of a protein is located by which method? 
Select and explain. 
A. Isoelectric pointing, B. Isoelectric cardiac failure, C. Ion exchange, D. pH
B: Isoelectric cardiac failure
Answer: B: Isoelectric cardiac failure 
Explanation: Ans. is 'b' i.e.,Isoelectric cardiac failure Isoelectric focusing is a procedure used to determine the isoelectric point (pI) of a protein.A pH gradient is established by allowing a mixture of low molecular weight organic acids and bases to distribute themselves in an electric field generated across the gel.When a protein mixture is applied, each protein migrates until it reaches the pH that matches its pI.Proteins with different isoelectric points are thus distributed differently throughout the gel.