Optimal Immobilization of Acidic Proteases from Monterey Sardine (Sardinops sagax caeurelea) on Partially Deacetylated Chitin from Shrimp Head Waste     

Jesus Aaron Salazar-Leyva  Jaime Lizardi-Mendoza  Juan Carlos Ramirez-Suarez  Elisa Miriam Valenzuela-Soto  Josafat Marina Ezquerra-Brauer  Francisco Javier Castillo-Yañez 《Journal Of Aquatic Food Product Technology》2013,22(7):1144-1154

ABSTRACT

Response surface methodology was employed to optimize the immobilization yield of acidic proteases from Monterey sardine (Sardinops sagax caeurelea) using partially deacetylated chitin as immobilization support. A rotatable central composite design was applied to evaluate the effects of immobilization conditions such as enzyme loading (X₁), immobilization pH (X₂), and tripolyphosphate concentration (X₃) on the immobilization yield. The analysis of variance revealed that the established model was significant (p < 0.05), and the adjustment of the quadratic model with the experimental data was satisfactory. Under optimal conditions (X₁ = 0.05 mg/mL, X₂ = 3.16, and X₃ = 0.75%), an immobilization yield of 79.1% was achieved; a value that was in accordance with the predicted one.  相似文献   

Partial characterization of alkaline proteases from viscera of vermiculated sailfin catfish Pterygoplichthys disjunctivus Weber, 1991     

Villalba-Villalba  Ana Gloria  Pacheco-Aguilar  Ramón  Ramirez-Suarez  Juan Carlos  Valenzuela-Soto  Elisa Miriam  Castillo-Yáñez  Francisco Javier  Márquez-Ríos  Enrique 《Fisheries Science》2011,77(4):697-705

Vermiculated sailfin catfish (Pterygoplichthys disjunctivus, Weber, 1991), a member of the Loricariidae family and an invasive species of several inland waters around the world, possess an enormous digestive tract representing about 10% of fish weight. Thus, the aim of this study was to partially characterize proteases from their digestive tracts. Azocasein digestion of the crude extract of intestine at different pH values and temperatures revealed the presence of alkaline proteases with optimum activities at pH 9.0 and 50°C. Incubation assays of the crude extract with inhibitors such as phenyl methyl sulfonyl fluoride, N-α-p-tosyl-l-lysine chloromethyl ketone, N-tosyl-phenyalanine chloromethyl ketone, benzamidine, pepstatin A and ethylenediamine tetra-acetic acid showed that trypsin and chymotrypsin are the main alkaline proteinases present. Zymography showed that the crude extract of Pterygoplichthys disjunctivus viscera contained proteases with molecular masses ranging from 21.5 to 116 kDa. Trypsin and chymotrypsin were inhibited by the following ions in decreasing order: Hg²⁺, Fe²⁺, Cu²⁺, Li⁺, Mg²⁺, K⁺, while Mn²⁺, and Ca²⁺ had no effect. Activities decreased continuously as the NaCl concentration increased from 0 to 30%. These results constitute important background information for future studies and for the potential biotechnological use of the crude digestive extract from this invasive species.  相似文献