Purification and Characterization of Chitinases from Ridgetail White Prawn Exopalaemon carinicauda

In this paper, we purified two native chitinases from the hepatopancreas of the ridgetail white prawn Exopalaemon carinicauda by using ion-exchange resin chromatography (IEC) and gel filtration. These two chitinases, named EcChi1 and EcChi2, were identified by chitinolytic activity assay and LC-ESI-MS/MS. Their apparent molecular weights were 44 kDa and 65 kDa as determined by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The specific activity of EcChi1 and EcChi2 was 1305.97 U center dot mg(-1) and 28.69 U center dot mg(-1). The optimal temperature and pH of EcChi1 were 37 degrees C and pH 4.0, respectively. Co2+, Fe3+, Zn2+, Cd2+, and Cu2+ had an obvious promoting effect upon chitinase activity of EcChi1. For colloidal chitin, the K-m and V-max values of EcChi1 were 2.09 mg center dot mL(-1) and 31.15 U center dot mL(-1)center dot h(-1).