A-1040 Ascomycin, >99% 
[Immunomycin] [FK-520] [FR-900520] [L 683590]
M.W. 792.01
C43H69NO12
[104987-12-4]
Storage:  Store at or below -20 ºC.  Solubility:  Soluble in DMSO at 65 mg/mL; soluble in ethanol at 50 mg/mL with warming; very poorly soluble in water; maximum solubility in plain water is estimated to be about 10-50 µM; buffers, serum, or other additives may increase or decrease the aqueous solubility.  Disposal:  A
Ascomycin (also known as Immunomycin, FR-900520, and FK-520) is an analog of tacrolimus (FK-506) with immunosuppressive, neurotrophic and antifungal activities.  Ascomycin can be used to prevent rejection after an organ transplant, and to treat autoimmune diseases and skin diseases.
Ascomycin inhibits the production of T helper type 1 (Th1) (interferon and IL-2) and Th2 (IL-4 and IL-10) cytokines in target cells.  Paul, C., et al.  "Ascomycins: promising agents for the treatment of inflammatory skin diseases."  Expert Opin. Investig. Drugs. 9:  69-77 (2000).  Mollison, K.W., et al.  "A macrolactam inhibitor of T helper type 1 and T helper type 2 cytokine biosynthesis for topical treatment of inflammatory skin diseases."  J. Invest. Dermatol. 112:  729-738 (1999).
Antimalarial effects of ascomycin appear to be independent of its immunosuppressive properties.  Monaghan, P., et al.  "Antimalarial effects of macrolactones related to FK520 (ascomycin) are independent of the immunosuppressive properties of the compounds."  J. Infect. Dis. 191:  1342-1349 (2005).
FK-520 might be a substrate for P-glycoprotein; expression of P-glycoprotein in yeast cells resulted in resistance to growth inhibition by FK-520.  Raymond, M., et al.  "Functional expression of P-glycoprotein in Saccharomyces cerevisiae confers cellular resistance to the immunosuppressive and antifungal agent FK520."  Mol. Cell Biol. 14:  277-286 (1994).