Okadaic acid

• CAT Number: R040026
• CAS Number: 78111-17-8
• Molecular Formula: C₄₄H₆₈O₁₃
• Molecular Weight: 805
• Purity: ≥95%
• Target: Protein Ser/Thr Phosphatases
• Solubility: Soluble in DMSO > 10 mM
• Storage: Desiccate at -20°C
• InChI: InChI=1S/C44H68O13/c1-25-21-34(55-44(23-25)35(46)12-11-31(54-44)24-41(6,50)40(48)49)26(2)9-10-30-14-18-43(53-30)19-15-33-39(57-43)36(47)29(5)38(52-33)32(45)22-28(4)37-27(3)13-17-42(56-37)16-7-8-20-51-42/h9-10,23,26-28,30-39,45-47,50H,5,7-8,11-22,24H2,1-4,
• InChIKey: QNDVLZJODHBUFM-WFXQOWMNSA-N
• SMILES: CC1CCC2(CCCCO2)OC1C(C)CC(C3C(=C)C(C4C(O3)CCC5(O4)CCC(O5)C=CC(C)C6CC(=CC7(O6)C(CCC(O7)CC(C)(C(=O)O)O)O)C)O)O

It is a potent protein phosphatase 1A and 2A inhibitor.

Polyether derivative of C-38 fatty acid, from the microorganism Prorocentrum lima
It is a very potent inhibitor of protein phosphatases-1 (PP1) and -2A (PP2A) that also stimulates the phosphorylation of many proteins. 1 nM completely inhibits PP2A with IC50 ~0.1 nM.IC50 = 10-15 nM for PP1. IC50 = 5 μM for PP2B.10 μM have no effect on PP2C.
It causes a durable contraction of isolated vascular smooth muscles from human umbilical arteries (0.1-100 μM) and rabbit aorta (10 μM), indicating that myosin P-light chain phosphorylation is increased.
It causes Diarrhetic Shellfish Poisoning (DSP), probably by stimulating the phosphorylation of proteins that control sodium secretion by intestinal cells. It is a powerful tumour promoter. In two-stage carcinogenesis experiments on mouse skin, is of comparable potency to agents like phorbol esters, which exert their effects by activating protein kinase C.
It reproduces the effects of Insulin on glucose transport in adipocytes.
It diffuses through the cell membrane.

Reference

– Haysted et al., /Effects of the tumour promoter okadaic acid on intracellular protein phosphorylation and metabolism./ Nature (1989). 337:78-81

– Cohen et al., /Okadaic acid: a new probe for the study of cellular regulation./ TIBS (1990). 15:98-102

– Shibata et al., /Contractile Effects of Okadaic Acid, a novel Ionophore-Like Substance from Black Sponge, on Isolated Smooth Muscles Under the Condition of Ca Deficiency./ J. Pharmacol. Exp. Therap. (1982). 233(1):135-143

– Cohen et al., FEBS Letters (1989). 250:596-600