The goal of this project is the synthesis of new inhibitors of the enzyme myristoyl-CoA:protein N-myristoyltransferase (NMT). This enzyme catalyzes the covalent modification of specific proteins by acylating the amino group of N-terminal glycines with myristoyl-CoA. Biomedically important proteins which are myristoylated include oncoproteins such as p60 src and the gag polypeptide of HIV and other retroviruses. The goal of this project is to design and synthesize inhibitors of protein myristoylation that are active in vivo for testing as anti-retroviral agents. More than 39 analogs of the substrate, myristoyl-CoA, or of the myristoylated peptide product have been synthesized to date. These include compounds designed to be either competitive or irreversible inhibitors of NMT. In addition, another 12 compounds have been obtained from commercial sources. All have been tested in an in vitro NMT assay developed within this project. Among the new compounds synthesized in our section, two have been determined to be highly potent inhibitors of protein myristoylation. Both have IC50 values below 0.1 uM. The regions of our substrate- and product-analogs that are necessary for high-affinity binding to NMT are being identified and incorporated into future syntheses. Two other synthetic compounds have shown activity in the NCI In Vitro Primary Antitumor Screen. One compound has specificity against the renal cancer panel, while the other primarily inhibits the growth of colon cancer lines. Both have been selected by the NCI Biological Evaluation Committee for further testing in rodents.
