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
Carboxylation of clotting factors by vitamin K isrequired to be biologically active. Which of the following amino acid is carboxylated? 
Select and explain. 
A. Histidine, B. Histamine, C. Glutamate, D. Aspaate
C: Glutamate
Answer: C: Glutamate 
Explanation: Glutamate [Ref: Harper 26/e p486/ See explanation of q no. 34 of Nov 2007.