Post‐translational modification of glutamate to gamma carboxyl glutamate is required for the
activity of vitamin K‐dependent proteins. Carboxylation is accomplished by the enzyme
gamma glutamyl carboxylase (GGCX) which requires the propeptide‐containing substrate
and three co‐substrates: reduced vitamin K, CO 2, and O 2. Most propeptides bind tightly to
GGCX and all of the Glu residues that will be modified are modified during one binding
event. Complete carboxylation is thus dependent upon the rate of carboxylation and the …