Okadaic Acid, Prorocentrum sp.

An ionophore-like polyether derivative of a C₃₈ fatty acid compound isolated from the dinoflagellates that have fed on the marine sponge Halinchrondria okadai. It is a potent non-comepetitive, reversible inhibitor of serine/threonine-specific protein phosphatases 1 (PP1, IC₅₀ = 10-15 nM, rabbit skeletal muscle, catalytic subunit) and 2A (PP2A, IC₅₀ = 0.1 nM, rabbit skeletal muscle, catalytic subunit). It has only a trivial effect on protein phosphatase 2B (IC₅₀ = 5 µM), a Ca²⁺/calmodulin-dependent enzyme, while PP2C, a Mg²⁺ dependent enzyme, is unaffected. Okadaic acid has no significant effect on the activities of tyrosine phosphatases, alkaline phosphatase, acid phosphatase, and inositol trisphosphatase. It is also a non-phorbol ester-type tumor promoter on mouse skin. Useful for the study of protein phosphatases and of PP1/PP2A in cell extracts, as well as in intact cells. Induces apoptosis in human breast carcinoma (MB-231 and MCF-7) and in myeloid cells, but inhibits glucocorticoid-induced apoptosis in T-cell hybridomas. Has marked contractile effect on smooth muscles and heart muscles. Implicated as a causative agent of diarrhetic shellfish poisoning.

An ionophore-like polyether derivative of a C₃₈ fatty acid compound that has tumor promoting properties. Potent inhibitor of protein phosphatase 1 (IC₅₀ = 10-15 nM) and protein phosphatase 2A (IC₅₀ = 0.1 nM). Does not affect the activity of tyrosine phosphatases, alkaline phosphatases, or acid phosphatases. Useful for the study of protein phosphatases in cell extracts as well as in intact cells. Induces apoptosis in human breast carcinoma cells (MB-231 and MCF7) and in myeloid cells but inhibits glucocorticoid-induced apoptosis in T cell hybridomas. Has marked contractile effects on smooth muscle and heart muscle. Implicated as causative agent of diarrhetic shellfish poisoning. A 250 µM (25 µg/124 µl) solution of Okadaic Acid, (Cat. No. 495609) in DMSO is also available.

Cell permeable: no

Primary Target
Protein phosphatase

Product does not compete with ATP.

Reversible: no

Target IC₅₀: 10-15 nM and 0.1 nM against protein phosphatase 1 and protein phosphatase 2A, respectively

Packaged under inert gas

Toxicity: Toxic (F)

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 1 month at -20°C.

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