Description_x000D_ General description_x000D_ Selenium (Se)-(Methyl) selenocysteine (MeSeCys) is a methylated product of selenocysteine, this reaction is catalyzed by selenocysteine methyltransferase (SMT) in Astragalus bisulcatus._x000D_ Application_x000D_ Se-(Methyl) selenocysteine hydrochloride has been used as a standard in fluorescence-XANES (X-ray absorption near-edge spectroscopy) imaging._x000D_ Packaging_x000D_ 100 mg in poly bottle_x000D_ Biochem/physiol Actions_x000D_ Selenium (Se)-(Methyl) selenocysteine functions as a potent chemotherapeutic agent for human breast cancer. Enhanced production of methlylselenol from L-Se-methylselenocysteine in vivo alters redox status of cells and oxidatively triggers cellular apoptosis. It is implicated in inhibition of mammary tumor formation in rats._x000D_ Se-(Methyl)selenocysteine is a chemopreventive agent that blocks cell cycle progression and proliferation of premalignant mammary lesions and induces apoptosis of cancer cell lines in culture.