Autolysis and proteolytic activity of cod viscera

Summary This paper describes the autolysis of cod viscera and discusses the importance of protease activity for this process. Autolysis yields a lipid phase, an aqueous soluble phase which contains much protein but very little lipid, and an insoluble sediment of protein and lipid. the amino acid composition of the soluble phase differs markedly from that of the sediment; the latter does not contain hydroxyproline and has relatively high levels of aromatic amino acids and of cysteine/cystine. the natural digestion process in the alimentary tract of cod also leaves an insoluble protein with a similar amino acid composition. the sediment which remains after autolysis is very resistant to the activity of the proteases present in the viscera. the pH curve for protease activity with a model substrate does not correspond to the pH curves for autolysis.