6-O-Methyl Mycophenolic Acid Methyl Ester is an impurity of Mycophenolic Acid(M831500) an antibiotic produced by Penicillium brevi-compactum, P. Stoloniferum and related spp. A selective inhibitor of lymphocyte proliferation by blocking inosine monophosphate dehydrogenase, an enzyme involved in the de novo synthesis of purine nucleotides.Environmental contaminants; Food contaminants