Rat liver vitamin K-dependent carboxylase: A study of antibodies raised against partially purified preparations of the enzyme

1. Antibodies raised against three preparations of increasing purity of the microsomal vitamin K-dependent carboxylase did not neutralize essential proteins in the enzyme complex. 2. When immobilized on Sepharose the antibodies removed 75% of contaminating proteins in the starting material, including cytochrome P-450. 3. Immunoaffinity chromatography was more efficient when carried out in the presence of the detergent CHAPS than in the presence of Triton X-100. 4. Immunoabsorption stimulated carboxylase activity 2.9-fold and resulted in a 66-fold increase in the specific activity of the complex.