| Abstract: | When the proteinases of the squid mantle muscle were extracted in the presence of dithiothreitol (DTT), the acid proteinase activity increased, indicating that the squid mantle muscle contains a considerable amount of the acid thiol proteinase. The crude extract hydrolyzed neither alpha-N-benzoyl-D,L-arginine-p-nitroanilide (BAPA) nor azocasein, thus refuting the presence of cathepsins B and L in the mantle muscle. The cathepsin D-like proteinase and the acid thiol proteinase were separated by Sephadex A-50 column chromatography. Each of the above partially purified proteinases was able to degrade carp actomyosin at pH 2.5 and 5.0, respectively. |
