The research proposal in this application is a supplement to a previously approved and funded Program in Thrombosis and Atherosclerosis. Dr. Friedman's portion of the program includes the synthesis and assaying of coumarin affinity labeling reagents which are to be introduced into in vitro systems which measure the metabolism and function of vitamin K. The studies are designed to determine which enzyme the coumarins block (i.e., carboxylase, epoxidase, epoxide reductase, DT diaphorase). Purification and characterization of proteins containing gamma carboxyglutamic acid is to be done from kidney, placenta, and spleen. A variety of in vivo and in vitro techniques including dietary manipulations and immunologic assays will be performed to attempt to identify roles for these tissue proteins.