It is produced by the strain of Streptomyces sp. MJ7420NF5. Dephostatin inhibits the activity of protein tyrosine phosphatase, has an IC50 of 7.7 moL/L against PTPase prepared from human tumor T cell lines, and it inhibits the growth of Jokat cells, and has a weak antibacterial activity (MIC 50~ 100 μg/mL).