Modification of Proteins with Proteolytic Enzymes from the Marine Environment

作者：Norman F. Haard, L.A.W. Feltham, N.B. Helbig, E. James Squires · 发表于：Advances in chemistry series · 年份：1982 · DOI：10.1021/ba-1982-0198.ch008 · 被引用次数：34 · 研究领域：Protein Hydrolysis and Bioactive Peptides、Meat and Animal Product Quality、Aquaculture Nutrition and Growth

Pepsin (E.C. 3.4.4.1) was isolated from the stomach lining of three marine fish ranging in habitat from arctic to temperate temperatures in the northwest Atlantic (arctic cod, Greenland cod, and American smelt). The fish pepsins had a more alkaline pH optimum than mammalian pepsins characterized thus far and pH optima were dependent on assay temperature. Fish pepsins exhibited activation energies for the hydrolysis of hemoglobin (pH 1.9) ranging from 4.1 to 8.8 kcal/mol in contrast to 11.2 kcal/mol for porcine pepsin. Activation energies were affected markedly by the assay pH for fish pepsins and only slightly affected for porcine pepsin. Temperature optima for fish pepsins were 15°-20°C lower than for porcine pepsin and the K′ m for hemoglobin was substantially higher for fish pepsins than for porcine pepsin. The K′ m for fish pepsins was variable with different assay temperatures. This chapter discusses low-temperature-adapted digestive enzymes and their utility as food-processing aids and the general importance of proteolysis in marine food products.