CAS No. 104987-12-4

Batch: Purity:99.71
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Ascomycin (FK520) Chemical Structure
Chemical Structure
Check the Ascomycin (FK520) product page for in-depth specifications, including solubility, stock solutions, MOA, and working concentrations.

Chemical Information

CAS Number 104987-12-4
Molecular Formula

C43H69NO12
Molecular Weight (MW) 792.01
SMILES CCC1C=C(CC(CC(C2C(CC(C(O2)(C(=O)C(=O)N3CCCCC3C(=O)OC(C(C(CC1=O)O)C)C(=CC4CCC(C(C4)OC)O)C)O)C)OC)OC)C)C

Ordering Information

Biological Activity

Ascomycin (FK520) is a potent macrolide immunosuppressant that selectively targets FK506-binding protein 12 (FKBP12). The resulting compound-protein complex interacts with and inhibits the serine/threonine phosphatase calcineurin within T lymphocytes. This phosphatase inhibition blocks the dephosphorylation and subsequent nuclear translocation of nuclear factor of activated T-cells (NFAT), ultimately impairing downstream cytokine gene expression and suppressing T-cell activation.

How to Prepare Stock Solution?

Concentration Volume Mass
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Solubility

Batch:
All in vitro solubility values are batch-tested experimental data (non-literature values).
Solvent Solubility & Note
DMSO 100 mg/mL (126.26 mM)
(Moisture-contaminated DMSO may reduce solubility. Use fresh, anhydrous DMSO. The recommended stock concentration is 10 mM in DMSO.)
Ethanol 100 mg/mL
Water Insoluble
FAQ
Q: Why does a DMSO stock precipitate in media/saline?
A: It is caused by unheated aqueous media (supersaturation), local solvent shock, or incorrect mixing sequence.
How to fix it?
  • Preheat media/saline to 37°C.
  • Mix rapidly (pipette/vortex) upon addition.
  • For complex mixes, always add the aqueous phase last.
  • Re-dissolve minor precipitates with a 37°C water bath and sonication (≤30 min).

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Note: Technical data last updated: Sep 1, 2026.