DISTRIBUTION OF PARVALBUMIN ISOTYPES IN ADULT SNOOK AND THEIR POTENTIAL APPLICATIONS AS SPECIES-SPECIFIC BIOMARKERS

The highly stable Ca2+ binding protein, parvalbumin, is prevalent in f ish white muscle tissue. The properties of this protein make it a prom ising antigen for use as a specific biomarker for fish identification. Parvalbumin was purified from white muscle of an adult common snook C entropomus undecimalis using ammonium sulfate precipitation, size-excl usion chromatography (SEC) and anion-exchange HPLC. Parvalbumins were characterized by the presence of an 11-kDa band following gradient-SDS gel electrophoresis and by their immunoreactivity against mouse anti- parvalbumin antibodies. Anion-exchange chromatography of the parvalbum in fraction separated from the SEC column yielded nine fractions. Subs equent analysis of these fractions by isoelectric focusing gel electro phoresis led to a total of seven parvalbumin isotypes, which may lend themselves as biomarkers in fish identification. The presence of these seven parvalbumin isotypes was confirmed independently by reversed-ph ase HPLC. A dilution endpoint immunoassay was developed for C. undecim alis parvalbumin using a monoclonal antibody directed against its high ly conserved calcium binding site. The utility of parvalbumin isotype distribution and specific monoclonal antibodies against fish parvalbum in. (C) 1997 The Fisheries Society oi the British Isles.