Carboxylation is a modification of glutamate (Glu) residues which occurs post-translation that is catalyzed by xcexb3-glutamyl carboxylase in the lumen of the endoplasmic reticulum. Vitamin K is a critical co-factor in the post-translational conversion of Glu residues to xcexb3-carboxyglutamate (Gla) residues. It has been shown that the process of carboxylation is involved in the blood clotting cascade, bone growth, and extraosseous calcification. However, studies in this field have been limited by the difficulty of experimentally studying substrate site specificity in xcexb3-glutamyl carboxylation. In silico investigations have the potential for characterizing carboxylated sites before experiments are carried out.