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 aminoacid carboxylated by vitamin K is 
Select and explain. 
A. Histidine, B. Aspartate, C. Proline, D. Glutamate
D: Glutamate
Answer: D: Glutamate 
Explanation: Vitamin  K  acts as a coenzyme for the carboxylation  of glutamic  acid residues present in the proteins and this reaction is catalysed by  a  carboxylase (microsomal).
Ref : Satyanarayana, 3rd ed, pg 130