Tacrolimus (Standard) is the analytical standard of Tacrolimus. This product is intended for research and analytical applications. Tacrolimus (FK506), a macrocyclic lactone, binds to FK506 binding protein (FKBP) to form a complex. Tacrolimus inhibits calcineurin phosphatase, which inhibits T-lymphocyte signal transduction and IL-2 transcription. Immunosuppressive properties[1].