Analytical and Bioanalytical Chemistry

, Volume 389, Issue 1, pp 335–342 | Cite as

Enzymatic hydrolysis of esterified diarrhetic shellfish poisoning toxins and pectenotoxins

  • Erin Doucet
  • Neil N. Ross
  • Michael A. QuilliamEmail author
Original Paper


Okadaic acid (OA) and dinophysistoxins-1 and -2 (DTX1, DTX2), the toxins responsible for incidents of diarrhetic shellfish poisoning (DSP), can occur as complex mixtures of ester derivatives in both plankton and shellfish. Alkaline hydrolysis is usually employed to release parent OA/DTX toxins, and analyses are conducted before and after hydrolysis to determine the concentrations of nonesterified and esterified toxins. Recent research has shown that other toxins, including pectenotoxins and spirolides, can also exist as esters in shellfish, but these toxins cannot survive alkaline hydrolysis. A promising alternative approach is enzymatic hydrolysis. In this study, two enzymatic methods were developed for the hydrolysis of 7-O-acyl esters, “DTX3,” and the carboxylate esters of OA, “diol-esters.” Porcine pancreatic lipase induced complete conversion of DTX3 to OA and DTXs within one hour for reference solutions. The presence of mussel tissue matrix reduced the rate of hydrolysis, but an optimized lipase concentration resulted in greater than 95% conversion within four hours. OA-diol-ester was hydrolyzed by porcine liver esterase and was completely converted to OA in less than 30 min, even in the presence of mussel tissue matrix. Esters and OA/DTX toxins were all monitored by LC–MS. Further experiments with pectenotoxin esters indicated that enzymatic hydrolysis could also be applied to esters of other toxins. Enzymatic hydrolysis has excellent potential as an alternative to the conventional alkaline hydrolysis procedure used in the preparation of shellfish samples for the analysis of toxins.


Diarrhetic shellfish poisoning (DSP) Okadaic acid Dinophysistoxins Pectenotoxins Esters Liquid chromatography–mass spectrometry Enzymatic hydrolysis 



We thank Drs. J. Aasen and T. Aune of the Norwegian School of Veterinary Science, Department of Food Safety and Infection Biology (Oslo, Norway) for contaminated shellfish tissue samples, Mr. W. Hardstaff and Ms. P. Blay for technical assistance, Ms. K. Boutilier for preliminary work with the esterase, and Drs. M. Laycock and T. Gill for valuable advice. Initial funding of ED’s graduate student support from Dr. J. Jellett (Jellett Rapid Testing Chester Basin NS) is gratefully acknowledged.


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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Erin Doucet
    • 1
    • 2
  • Neil N. Ross
    • 1
  • Michael A. Quilliam
    • 1
    Email author
  1. 1.National Research Council CanadaInstitute for Marine BiosciencesHalifaxCanada
  2. 2.Department of Process Engineering and Applied Science, Food Science ProgramDalhousie UniversityHalifaxCanada

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