Purification and characterization of a cold-adapted κ-carrageenase from Pseudoalteromonas sp. ZDY3

kappa-Carrageenase (EC3.2.1.83) is a class of glycoside hydrolase, which can be used for hydrolysis of kappa-carrageenan to kappa-carrageenan oligosaccharides. In this study, a bacterium, identified as Pseudoalteromonas sp. ZDY3 isolated from rotten algae, was capable to degrade kappa-carrageenan. The x-carrageenase produced by Pseudoalteromonas sp. ZDY3 was purified to homogeneity and named as CgkZDY3. The accurate molecular mass of CgkZDY3 was determined through LC-HRMS, and a posttranslational removal of C-terminal end of the protein was discovered. CgkZDY3 had strict hydrolysis specificity to kappa-carrageenan, the values of K-m and k(cat)/K-m of CgkZDY3 were 3.67 mg mL(-1) and 53.0 mL mg(-1) s(-1), respectively. CgkZDY3 was a cold-adapted kappa-carrageenase with excellent storage stability of both the temperature below 35 degrees C and a wide pH range, and was an endo-type kappa-carrageenase with high hydrolysis rate, oligosaccharides with different degrees of polymerization can be obtained by controlling the hydrolysis time, and the final products were kappa-neocarrabiose and kappa-neocarratetraose. These properties are of great significance for production of kappa-carrageenan oligosaccharides with different polymerization degrees under process control.