Gamma - Carboxylation of which of the following requires vitamin K?
High-Yield Explanation
IVitamin K Function 1. Cataelyzes gamma-carboxylation of glutamic acid residues on various proteins concerned with blood clotting. 2. Catalyzes gamma-carboxylation of glutamic acid to GABA. Deficiency 1.Neonatal hemorrhage with increased PT and aPTT, but normal bleeding time. 2. Synthesized by intestinal flora, so vitamin-K deficiency can occur after the prolonged 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 impoant in diagnosing vitamin K deficiency. Ref: Biochemistry by U. Satyanarayana 3rd edition Pgno : 129