• Two inhibitors of ACAT2 reduced the esterification of okadaic acid. • Five inhibitors of ACAT1 had no significant effect on okadaic acid esterification. • ACAT 2 concentration is directly related to that of okadaic acid. • ACAT1 and LCAT immunoreactivities are not related to okadaic acid concentration. • ACAT2 or a homolog enzyme should be responsible for okadaic acid esterification. Harmful algal blooms of Dinophysis species produce diarrhetic shellfish poisoning toxins like okadaic acid (OA) that accumulate in shellfish, posing health risks and economic losses. This study investigated the enzymes involved in OA esterification, a key detoxification process in shellfish. Experiments using enzyme inhibitors and quantification of acyltransferases in mussels with varying OA levels suggest that one homolog of human acyl-CoA cholesterol acyltransferase 2 (ACAT2) is the main enzyme responsible for OA esterification. Mammal ACAT2 inhibitors reduced OA esterification in mussel digestive gland tissue. Additionally, immunoreactivity to human antibodies (ELISA) correlated positively with OA concentrations in naturally contaminated mussels. The tissue distribution and subcellular localization of the ACAT2 homolog also support its role in OA detoxification. These findings provide new insights into the mechanism of OA depuration in shellfish and may inform strategies to enhance detoxification rates.
Blanco et al. (Sun,) studied this question.