DIFFERENTIATION OF SCOMBROID FISH SPECIES (TUNAS, BONITOS AND MACKERELS) BY ISOELECTRIC-FOCUSING, TITRATION CURVE ANALYSIS AND NATIVE POLYACRYLAMIDE-GEL ELECTROPHORESIS OF SARCOPLASMIC PROTEINS

Differentiation of scombroid fishes was possible by electrophoresis of sarcoplasmic proteins using either isoelectric focusing (IEF), titrat ion curve analysis, or native polyacrylamide gel electrophoresis (PAGE ). By IEF with Phast-Gels 3-9 species specific patterns, characterized by a few bands in the cathodal part of the gels, were obtained. This type of gel was also used for titration curve analysis. Here, too, the closely related species Thunnus thynnus and T. albacares gave differe nt protein patterns. Native PAGE, native cathodal electrophoreses in C lean Gel 10% with buffer pH 5.5, proved to be a fast and simple method for differentiation of scombroid fishes. As most of the prominent sar coplasmic proteins of these species have pls in the neutral or alkalin e pH range, they are positively charged at pH 5.5 and move to the cath ode.