Tirpenou A. E.

Conventional electroforetic techniques generally lack the resolution and reproducibility needed for a reliable identification of fish species. Only isoelectric focusing on ultrathin poyacrylamide layer can give a high resolution protein separation of sarcopasmic proteins. This technique gives reproducible, species specific patterns of the sarcoplasmic proteins of fish which are separated accoding to their isoelectric point (pI) on the polyacrylamide layer with a steadily reproducible natural pH gradient (3-10). Protein patterns se produced could be used as a permanent file for the unknown fish species identification. Problems arising from thw preparation of the gel (carcinogenic) were overcome by the use of ready made plates, gloves and forceps. A large number of fish were tested, fresh and frozen at -140C as well as at -350C . It was observed that long-term frozen storage of fish as a whole of fish sarcoplasmic protein extracts (>6 months) causes denaturation of certain proteins which disappear from the protein pattern.