The morpholinoethyl ester of mycophenolic acid (MPA) with potent immunosuppressive properties. Mycophenolate stops T-cell and B-cell proliferation through selective inhibition of the de novo pathway of purine biosynthesis. In vivo, the active metabolite, MPA, reversibly inhibits inosine 5'-monophosphate dehydrogenase, an enzyme involved in the de novo synthesis of guanine nucleotides. MPA displays high lymphocyte specificity and cytotoxicity due to the higher dependence of activated lymphocytes on both salvage and de novo synthesis of guanine nucleotides relative to other cell types. or A drug used to prevent graft-versus-host disease (GVHD) after organ transplants. It is also being studied in the prevention of GVHD after stem cell transplants for cancer, and in the treatment of some autoimmune disorders. Mycophenolate mofetil is a type of immunosuppressive agent. Also called CellCept.