Abstract
The occurrence of the carbon-phosphorus compound 2-aminoethylphosphonic acid (2-AEP) in sixteen species of edible shellfish is demonstrated.
Edible shellfish have previously been found to contain 2-AEP, and the present study adds a number of new species to the positive list. 2-AEP was found in the chloroform-methanol-soluble (lipid) and TCA-insoluble fractions of the samples. About 21, 9, 5 and 2 mg of 2-AEP were isolated from the lipid of freeze-dried material from Tengunishi Hemifusus ternatanus (134g), Uchiwaebi Ibacus ciliatus (55g), Gazami Portunus trituberculatus (16g) and Uni Hygrosoma hoplacantha (32g), respectively. The compound was purified by a combination of ion-exchange column chromatography with Dowex 50-X4 and Dowex 1-X8 resins. The infrared spectrum of the isolated compound showed an absorption band at 1, 180 cm-1 due to a C-P bond, and was essentially identical with that of authentic 2-AEP. Hydrolysis of the compound by a strong acid resulted in neither an change in the chromatographic behavior of this compound nor in the liberation of inorganic phosphate. The stability of the compound to acid hydrolysis suggests the presence of a C-P bond. Comparison with a synthetic compound indicated that the aqueous hydrolysis product behaved like 2-aminoethylphosphonic acid on a thin-layer chromatogram. The sixteen species of edible shellfish selected here each had a relatively high concentration of 2-AEP.
