Gelatinolytic activities in muscle of Atlantic cod (Gadus morhua), spotted wolffish (Anarhichas minor) and Atlantic salmon (Salmo salar)

The gelatinolytic activity in muscle from Atlantic cod (Gadus morhua), spotted wolffish (Anarhichas minor) and Atlantic salmon (Salmo salar) was studied using gelatin SDS-PAGE, gelatin affinity chromatography and enzyme inhibitors. These fish species are known to differ markedly in fillet softening and gaping post mortem. Atlantic cod, which is a promising species for cold water marine aquaculture, often shows such negative properties, particularly after being well fed. Gelatinolytic activity bands were present in all three species. Using gelatin chromatography and enzyme inhibitors, both serine proteinases and metalloproteinases were detected in wolffish and cod muscle, while only the latter were found in salmon muscle. Activation of the metalloproteinases by p-aminophenylmercuric acetate (APMA) resulted in a shift in activity from higher to lower molecular weight, as is known for mammalian matrix metalloproteinases. In all three species the molecular weight of the metalloproteinases was lowered from approximately 80 to about 70 kDa by activating with APMA.