Specific enzyme detection following isoelectric focusing as a complimentary tool for the differentiation of related Gadoid fish species

The presence of specific enzymes in the sarcoplasmic protein fraction of ei ght gadoid fish species has been investigated following isoelectric focusin g (IEF) in the 3.5-9.5 pH range. Lactate dehydrogenase (LDH) and glycerol-3 -phosphate-dehydrogenase (G-3-PD) allowed the differentiation of most of th e gadoids tested, even in the case of closely related species belonging to the genus Merluccius. Investigation of arginine kinase and creatine kinase afforded non-specific enzyme patterns in the species tested. Adenylate kina se and malate dehydrogenase did not give specific or reproducible enzyme pa tterns. Analysis of LDH and G-3-PD activities in commercial IEF gels was sh own to be a reliable and reproducible technique for distinguishing closely related Merluccius spp. and other gadoid fish species. (C) 2000 Elsevier Sc ience Ltd. All rights reserved.