Characterisation of choline esterases and their tissue and subcellular distribution in mussel (Mytilus edulis)

Margaret Brown*, Ian M. Davies, Colin F. Moffat, John Redshaw, John A. Craft

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)


Acetylcholinesterase in mussel is potentially a useful biomarker of exposure to organophosphates (OP) in the marine environment. This study looked at cholinesterase activity in subcellular fractions of various tissues from the common mussel, Mytilus edulis. Measurement of enzyme rates demonstrated that although highest specific activity was found in foot 'mitochondrial' fraction, recovery of activity was very low. Gill 'microsomal' fraction had the second highest specific activity with a useful level of recovery and therefore was the most suitable tissue fraction for biomarker applications. Comparative studies of alternative alkylthiocholine substrates and competitive inhibitors suggest there is a single cholinesterase enzyme type present in this fraction. Inhibition of alkylcholine hydrolysis by BW284C51, specific to acetylcholinesterase in vertebrates, showed that cholinesterase activity in gill 'microsomal' fraction is inhibited by this compound but to a lesser extent than in vertebrate AChE. Inhibition of cholinesterase activity by azamethiphos in gill 'microsomal' fraction gave an IC50 of approximately 100 μM and showed both time and concentration dependence. However this indicates a lower potency compared to other animals and it is debatable whether mussel cholinesterase activity is useful as a biomarker of exposure in the field.
Original languageEnglish
Pages (from-to)155-169
Number of pages15
JournalMarine Environmental Research
Issue number3
Early online date10 Sept 2003
Publication statusPublished - Apr 2004


  • Azamethiphos
  • Biomarkers
  • Cholinesterase
  • Mussel
  • Mytilus edulis
  • Organophosphates

ASJC Scopus subject areas

  • Oceanography
  • Aquatic Science
  • Pollution


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