What molecule am I?
Okadaic acid1, a nasty marine toxin, is a complex multiring polyether found in certain dinoflagellates, single-cell eukaryotes of the genera Dinophysis and Thorecta. It typically accumulates in sea sponges and shellfish. in 1981 by Paul J. Scheuer, Jon Clardy, Francis J. Schmitz, and collaborators at the University of Hawaii at Manoa (Honolulu), Fujisawa Pharmaceutical (Tokyo), Cornell University (Ithaca, NY), and the University of Oklahoma (Norman) in the sponges Halichondria okadai (for which it was named) and H. melandocia.
Okadaic acid is a potent inhibitor of serine鈥搕hreonine phosphatase subclasses PP2A, PP1, and PP2B. (PP stands for protein phosphatase.) It is the inhibition of this enzyme that is a primary cause of diarrheic shellfish poisoning (DSP) in humans. In addition to diarrhea, DSP can cause abdominal pain, nausea, and vomiting.
In 2013, Vanessa Valdiglesias and coauthors at the University of A Coru帽a (Spain) published a review of other harmful effects of okadaic acid. They discussed studies that reported the compound鈥檚 role in . At that time, no reported data indicated that these toxicities cause chronic or subchronic effects in humans; but the authors believed that more research should be done in this area. On the positive side, they stated that okadaic acid is a useful tool for studying cellular signaling because of its selective inhibition of protein phosphatase activity.
For updated information on okadaic acid, see the molecule鈥檚 page.
1. SciFinder: 1,7-dioxaspiro[5.5]undec-10-ene-2-propanoic acid, 伪,5-dihydroxy-伪,10-dimethyl-8-[(1R,2E)-1-methyl-3-[(2R,4鈥瞐R,5R,6鈥�S,8鈥�R,8鈥瞐S)-辞肠迟补丑测诲谤辞-8鈥�-丑测诲谤辞虫测-6鈥�-摆(1S,3S)-1-hydroxy-3-[(2S,3R,6S)-3-尘别迟丑测濒-1,7-诲颈辞虫补蝉辫颈谤辞摆5.5闭耻苍诲别肠-2-测濒闭产耻迟测濒闭-7鈥�-尘别迟丑测濒别苍别蝉辫颈谤辞摆蹿耻谤补苍-2(3H),2鈥� (3鈥�H)-pyrano[3,2-b]pyran]-5-yl]-2-propen-1-yl]-, (伪R,2S,5R,6R,8S)-.
Okadaic acid听hazard information
| Hazard class* | GHS code and hazard statement | |
|---|---|---|
| Acute toxicity, oral, category 3 | H301鈥擳oxic if swallowed |  |
| Acute toxicity, dermal, category 3 | H311鈥擳oxic in contact with skin | |
Skin corrosion/irritation, category 2 | H315鈥擟auses skin irritation |  |
Acute toxicity, inhalation, category 3 | H331鈥擳oxic if inhaled | |
*Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. .
Molecules from the journals
Titanium diboride1 (TiB2) is one of the hardest known ceramic materials, especially in the temperature range 1000鈥�3000 掳C. It has other excellent properties, including high thermal and electrical conductivities and the highest elastic modulus, fracture toughness, compressive strength, and melting point of all boride ceramics.
Last month, Satadru Chakrabarty and Kabeer Jasuja* at the Indian Institute of Technology Gandhinagar described another valuable aspect of TiB2. When formed into a gel-like, oxygen-functionalized nanosheet dispersion, 2 to change the color of the dispersion from yellow to orange. The reaction also disrupts the cross-links between the borate groups on the nanosheets that are responsible for the gel structure of the dispersion.
Pterodactylane3鈥攖etracyclo[4.4.0.02,5.07,10]decane鈥攊s a hydrocarbon with four cyclobutane rings connected linearly. It was by Rangaswamy Srinivasan* and K. A. Hill at the IBM Watson Research Center (Yorktown Heights, NY) via the photolysis of benzene. Although the C4H10 product can exist in three positional isomers, only one isomer was produced.
Pterodactylane is so named because its structure resembles the wings of a pterodactyl in flight. It is also called [4]-ladderane, one of a series of fused cyclobutane molecules whose structures take the shape of a ladder.
In December, Stephen L. Craig, Todd J. Mart铆nez, Yan Xia, and collaborators at Stanford University (CA), Duke University (Durham, NC), and Heinrich Heine University (D眉sseldorf, Germany) described the . In one study, they prepared pterodactylanes with substituents on the central rung and on the end rung. When they applied outward forces to the substituents, they were surprised to find that the threshold force for bond breaking is dramatically lower for the central rung (0.7 nN) than the end rung (1.9 nN).
1. CAS Reg. No. 12045-63-5.
2. CAS Reg. No. 50-81-7.
3. CAS Reg. No. 4466-29-9.
Molecules from the Journals
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Okadaic acid听fast facts
| CAS Reg. No. | 78111-17-8 |
| Empirical formula | C44H68O13 |
| Molar mass | 805.00 g/mol |
| Appearance | White crystals or powder |
| Melting point | 164鈥�166 掳C 171鈥�174 掳Ca |
| Water solubility | Insoluble |
a. Both values appear in the chemical literature.
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