摘要
κ-Carrageenase(EC 3.2.1.83)is a glycoside hydrolase that efficiently breaks downκ-carrageenan intoκ-carrageenan oligosaccharides(κ-COS).In this study,a novel GH16 familyκ-carrageenase called CeCgkB was cloned from the genome of Colwellia echini.Escherichia coli BL21(DE3)was used to express CeCgkB.CeCgkB has a complete length of 987 bp,encoding 329 amino acid residues,and a molecular weight of 37.44 kDa.Biochemical characterization indicated that CeCgkB exhibits cold-adapted properties and was able to reach a maximum activity of 1530 U/mg at pH 8.0 and 35℃.Kinetic parameters showed that CeCgkB has a low Km value(2 mg/mL),indicating high substrate affinity.As an endo-typeκ-carrageenase,CeCgkB can degradeκ-carrageenan into products of varying DP,with a preference for DP4,DP6,and DP10.ESI-MS analysis revealed that the major products of CeCgkB consist ofκ-carratetraose,κ-carrahexaose,andκ-carradecaose.As a result of CeCgkB’s high activity,cold-adapted,and principal products,it is a promising biotechnological tool for the efficient preparation ofκ-carrageenan oligosaccharides.
基金
supported by the National Natural Science Foundation of China(32372268).
