M.W. 805.01

C44H68O13

M.I. 12: 6958

[78111-17-8] RTECS: AA8227800

WARNING:  Highly irritant to skin and mucous membranes.  SPECIAL HAZARD:  TUMOR PROMOTER.  Gloves and mask should be worn when using this compound.  Care must be taken to prevent contact through all routes of exposure.

Storage:  Store at or below -20 ºC.  Solubility:  Soluble in DMSO or ethanol.  Disposal:  A

Potent inhibitor of protein phosphatases, especially the PP-1 and PP-2 classes, in numerous cell types.  Cohen, P. et al.  Trends Biochem. Sci. 15:  98-102 (1990).

Non-phorbol type tumor promoter.  Suganuma, M. et al.  Proc. Natl. Acad. Sci. USA 85:  1768-1771 (1988).

Please request Technical Note #18 for additional information.

Important Notes on Stability:

1. We believe this product and the three okadaic acid salts below, as shipped from our inventory, are the purest and most stable okadaic acid products available anywhere.  In contrast, material from other vendors is often degraded and quite impure.  Long-term stability of our four okadaic acid products in their unopened ampules is excellent.
2. All four okadaic acid products must first be dissolved in an organic solvent to prepare stock solutions.  The okadaic acid molecule is large and somewhat hydrophobic, and material may not be reliably dissolved out of the ampule with purely aqueous solutions.  We understand that some practitioners use mixed aqueous/organic solvents to dissolve material out of the ampules, but we have not tested the efficacy of this approach ourselves.
3. Solutions of the free acid form of okadaic acid in organic solvents are distinctly less stable, even in the freezer, than those made from the three salt forms listed below.
4. Once diluted into aqueous media (and assuming equal starting purities), the information available to us indicates that all four forms of okadaic acid show comparable stability.
5. The biological activity of all four products is identical for the okadaic acid portion, but obviously the counter-ions themselves may affect ion-sensitive experimental systems.
6. In summary:  ignoring the counter-ions, all four forms of okadaic acid are biologically equivalent and equally useful if made up as a stock solution in an organic solvent and used within a fews days.  If freezer storage of an organic solvent-based stock solution of okadaic acid is anticipated to extend beyond a week or so, we recommend a salt form rather than the free acid.