IMMUNOLOGICAL CHARACTERIZATION OF METALLOTHIONEIN IN MARINE AND FRESH-WATER FISH

Metallothionein (MT) is a low-molecular-weight, cysteine-rich, metal-b inding protein found in all vertebrates. The primary structure of the protein is evolutionary conserved, especially the location of cysteine -residues. There are nonetheless significant differences between MTs f rom different vertebrate classes, notably in major antigenic epitopes. Previous work has shown that MT from different fish species also diff er. The objective of the present work was to characterize MT from temp erate, sub-tropical and tropical fish species by their relative reacti vities with two anti-fish MT antisera. One or both antisera cross-reac ted with MT from all fish species investigated. Surprisingly, the rela tive reactivities of the two antisera with MT from species belonging t o different taxonomic groups appeared to reflect differences at the le vel of family rather than differences between major phylogenetic linea ges.