What essential role does vitamin K play in the posttranslati

What essential role does vitamin K play in the post-translational modification of glutamic acid residues? What two proteins involved in blood clotting and bone formation require this modification to function?

Solution

Vitamin K plays a role of cofactor in the carboxylation of glutamic acid residues. the reaction is catalyzed by the enzyme gamma-glutamyl carboxylase (-glutamyl carboxylase). The result of this type of reaction is the formation of a -carboxyglutamate (gamma-carboxyglutamate),

The two proteins which requires the modified glutamic acid residues are:

factor IXa

Osteocalcin