title: Vitamin K-dependent carboxylase: possible role of the substrate "propeptide" as an intracellular recognition site.
abstract: The liver microsomal vitamin K-dependent carboxylase catalyzes the posttranslational conversion of specific glutamate residues to gamma-carboxyglutamate residues in a limited number of proteins. A number of these proteins have been shown to contain a homologous basic amino acid-rich "propeptide" between the leader sequence and the amino terminus of the mature protein. Plasmids encoding protein C, a vitamin K-dependent protein, containing or lacking a propeptide region were constructed and the protein was expressed in Escherichia coli. The protein products were assayed as substrates in an in vitro vitamin K-dependent carboxylase system. Only proteins containing a propeptide region were substrates for the enzyme. These data support the hypothesis that this sequence of the primary gene product is an important recognition site for this processing enzyme.
mesh_terms: D000818:Animals; D019735:Carbon-Carbon Ligases; D002417:Cattle; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D007106:Immune Sera; D008025:Ligases / Q000235:genetics* / Q000378:metabolism; D008862:Microsomes, Liver / Q000201:enzymology*; D010957:Plasmids; D011486:Protein C / Q000378:metabolism; D011487:Protein Conformation; D011516:Prothrombin / Q000378:metabolism; D051381:Rats; D014813:Vitamin K Deficiency / Q000201:enzymology
chemical_list: D007106:Immune Sera; D011486:Protein C; D011516:Prothrombin; D008025:Ligases; D019735:Carbon-Carbon Ligases; C020660:glutamyl carboxylase