title: Separation of cathepsin D-like proteinase and acid thiol proteinase of squid mantle muscle.
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.
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D002347:Carps; D002402:Cathepsin D; D002403:Cathepsins / Q000302:isolation & purification*; D055598:Chemical Phenomena; D002621:Chemistry; D003546:Cysteine Endopeptidases; D049832:Decapodiformes / Q000201:enzymology*; D010450:Endopeptidases / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D009132:Muscles / Q000201:enzymology
chemical_list: D000205:Actomyosin; D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002402:Cathepsin D