title: PP2A inhibition assay using recombinant enzyme for rapid detection of okadaic acid and its analogs in shellfish.
abstract: Okadaic acid and its analogs (OAs) responsible for diarrhetic shellfish poisoning (DSP) strongly inhibit protein phosphatase 2A (PP2A) and thus are quantifiable by measuring the extent of the enzyme inhibition. In this study, we evaluated the suitability of the catalytic subunit of recombinant human PP2A (rhPP2Ac) for use in a microplate OA assay. OA, dinophysistoxin-1(DTX1), and hydrolyzate of 7-O-palmitoyl-OA strongly inhibited rhPP2Ac activity with IC(50) values of 0.095, 0.104, and 0.135 nM, respectively. The limits of detection and quantitation for OA in the digestive gland of scallops and mussels were 0.0348 μg/g and 0.0611 μg/g respectively, and, when converted to the whole meat basis, are well below the regulation level proposed by EU (0.16 μg/g whole meat). A good correlation with LC-MS data was demonstrated, the correlation coefficient being 0.996 with the regression slope of 1.097.
authors: Tropical Technology Center Ltd., 5-1 Suzaki, Uruma, Okinawa 904-2234, Japan. tikehara@ttc.co.jp
authors: Tsuyoshi
authors: T
authors: Ikehara
authors: Shihoko
authors: S
authors: Imamura
authors: Atsushi
authors: A
authors: Yoshino
authors: Takeshi
authors: T
authors: Yasumoto
mesh_terms: D000818:Animals; D049872:Bivalvia; D006801:Humans; D008387:Marine Toxins; D019319:Okadaic Acid / Q000031:analogs & derivatives; D054648:Protein Phosphatase 2; D012758:Shellfish; D057096:Shellfish Poisoning
chemical_list: D008387:Marine Toxins; D019319:Okadaic Acid; D054648:Protein Phosphatase 2