Protein Tyrosine Phosphatases (PTPs) are enzymes that remove phosphate from tyrosine residues of cellular proteins. They are believed to play an active role in such diverse pathological events as diabetes, cancer and immune deficiency. Rational design of inhibitors which can act with a high specificity and selectivity towards certain PTPs will be the aim of our project which will be carried out at Dr. S. Toxvaerd's laboratory in close collaboration with Novo Nordisk's computational group. Drug design computational techniques such as LUDI, HOOK, Leapfrog, etc. will be used to generate the drug candidates. Ligand /protein affinity will be evaluated using different computational techniques. Molecular dynamics simulations will provide relevant information on the binding affinity and selectivity of the designed inhibitors. Ab initio methods will be used to parametrize the force fields used in the system minimizations and dynamics simulations.