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
The following enzyme activity is measured in Beriberi: 
Select and explain. 
A. Decarboxylase, B. Deaminase, C. Transketolase, D. Transaminase
C: Transketolase
Answer: C: Transketolase 
Explanation: In thiamine deficiency transketolase activity in erythrocytes is decreased. Measures of RBC transketolase is a reliable diagnostic test for thiamine deficiency. Beriberi is caused by thiamine deficiency. Ref: Clinical Laboratory Medicine, 2nd Ed, Page 322