This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Carbohydrates, Subject name: Biochemistry
Essential fructosuria is due to the deficiency of which enzyme? 
Select and explain. 
A. Aldolase A, B. Aldolase B, C. Fructokinase, D. Glucokinase
C: Fructokinase
Answer: C: Fructokinase 
Explanation: Ans. (c) FructokinaseRef: Harper, pg. 169"Deficiencies in the enzymes of fructose and galactose metabolism lead to essential fructosuria and galactosemias""Lack of hepatic fructokinase causes essential fructosuria, and absence of hepatic aldolase B, which cleaves fructose 1-phosphate,leads to hereditary fructose intolerance"Metabolism of fructose. Aldolase A is found in all tissues, whereas aldolase B is the predominant form in liver. (not found in liver)