<prompt> Vit K is needed for which of these post transational modification processes-MethylationCarboxylationHydroxylationTransketolation  <response>: Ans. is b i.e., Carboxylation : The main function of vit K is the promotion of blood coagulation by helping in the post transcriptional modification of blood factors such as II, VH,IX,X 2, 7, 9, 10 . Vit. K functions as a coenzyme for carboxylase. This converts the glutamate residues into Gamma carboxy glutamate residues. 