Purification and characterization of anionic proteases from the hepatopancreas of crawfish, procambarus clarkii

Four electrophoretically homogenous anionic proteases from crawfish hepatopancreas were purified via acetone fractionation, benzamidine Sepharose 6B, DEAE-Sephacel, and Sephacryl S-200 column chromatography. Purity was increased 50, 36, 27, and 50-fold with approximately 2.1, 2.9, 1.6, and 2.3% yield for protease A,B,C, and D, respectively. Apparent Michaelis-Menten (Km’) constants of protease A,B,C, and D were similar at pH 6.8 and 8.1. Protease A had the highest substrate turnover number followed by protease D compared with the other proteases at pH 8.1. Thus, these two enzymes may play a primary role in the development of mushniss in crawfish tail meat compared with other proteases.