COMPARISON BETWEEN ISOLATION PROTOCOLS COMMONLY USED FOR THE PURIFICATION OF MOLLUSK METALLOTHIONEINS

Two centrifugation methods (at 30 000 and 100 000 g) combined with two isolation procedures (heat denaturation and solvent precipitation) we re tested to check if their use introduced significant differences in the quantification of metals (Cd, Cu, Zn) and metallothioneins in blue mussel organs (gills and digestive gland). No contaminating compounds originating from the lowest centrifugation speed,were likely to inter fere with quantitative measurements of metal, protein and metallothion ein. As isolation treatments act on specific properties of proteins in general and metallothionein isoforms in particular they cannot be use d interchangeably,. Therefore, any comparisons of MT amounts in bivalv e tissues with data from the literature have to take into account the isolation procedure. Similar results were obtained with three other mo lluscs, Crassostrea gigas, Bathymodiolus thermophilus thermophilus (hy drothermal mussel), and Corbicula fluminea (estuarine bivalve). (C) 19 98 Elsevier Science Ltd All rights reserved.