Gamma - Carboxylation of what requires vitamin k?
Vitamin K
Function
1.   Catalyzes gamma-carboxylation of glutamic acid residues on various proteins concerned with blood clotting.
2.   Catalyzes gamma carboxylaton of glutamic acid to GABA.
Deficiency
1.   Neonatal haemorrhage with increased PT and aPTT, but normal bleeding time.
2.   Synthesized by intestinal flora, so vitamin-K deficiency can occur after the prelonged use of broad-spectrum antibiotics.
      (Note: Vitamin-K dependent clotting factors are II, VII, IX, X and protein C and S. Warfarin is a vitamin-K antagonist)
      A specific protein known as PIVKA (Protein induced in vitamin K absence) is important in diagnosing vitamin K deficiency.
Glutamine
Glutamic Acid
Glycine
Aspartate