Chemical. CAS 159351-69-6. Formula C53H83NO14. MW 958.2. Isolated from Streptomyces hygroscopicus. Macrolide antibiotic, inhibiting bacterial protein synthesis. Orally available Rapamycin derivative that shows improved pharmacokinetics and pharmacodynamics. Potent immunosuppressant. Binds with high affinity to the FK506 binding protein-12 FKBP-12 to generate an immunosuppressive complex that inhibits the activation of the mammalian target of rapamycin mTOR. More selective for the mTORC1 protein complex, with little impact on the mTORC2 complex, compared to Rapamycin. Since mTORC2 is believed to play an important role in glucose metabolism and the immune system, selective inhibition of mTORC1 achieves many of the benefits of rapamycin without the associated glucose intolerance and immunosuppression Anticancer agent.