Conversion of pectenotoxin-2 to pectenotoxin-2 seco acid in the New Zealand scallop, Pecten novaezelandiae

Comparison of pectenotoxin (PTX) profiles between the toxic dinoflagellate Dinophysis acuta and scallops Pecten novaezelandiae collected at Wedge Poin t, Queen Charlotte Sound, New Zealand was carried out by liquid chromatogra phy-mass spectrometry (LC-MS) with turbo-ionspray ionization. Although the major PTX homolog in D. acuta was pectenotoxin-2 (PTX2), the scallops conta ined pectenotoxin-2 seco acid (PTX2SA) as the predominant toxin. Pectenotox in-2 isolated from D. acuta was rapidly converted to PTX2SA and its epimer 7-epi-pectenotoxin-2 seco acid (7-epi-PTX2SA) in the scallop extracts. Thes e results indicate that PTX2SA and 7-epi-PTX2SA arose from the conversion o f PTX2 by scallop tissue. The results indicate that New Zealand scallops ha ve an ability to reduce the cytotoxicity of PTX2 by conversion to PTX2SA.