A novel enzyme, lambda-carrageenase, isolated from a deep-sea bacterium

J Biochem. 2006 Oct;140(4):475-81. doi: 10.1093/jb/mvj180. Epub 2006 Aug 22.


A lambda-carrageenan-degrading Pseudoalteromonas bacterium, strain CL19, was isolated from a deep-sea sediment sample. A lambda-carrageenase from the isolate was purified to homogeneity from cultures containing lambda-carrageenan as a carbon source. This is the first report of the isolation of lambda-carrageenase together with the gene sequence for the enzyme. The molecular mass of the purified enzyme was approximately 100 kDa on both SDS-PAGE and gel-filtration chromatography, suggesting that the enzyme is a monomer. The optimal pH and temperature for activity were about 7 and 35 degrees C, respectively. The enzyme had specific activity of 253 U/mg protein. The enzyme required monovalent salts for the activity. Carbohydrates, such as sorbitol, sucrose, trehalose, improved the enzyme stability. The pattern of lambda-carrageenan hydrolysis showed that the enzyme is an endo-type lambda-carrageenase, and the final main product was a tetrasaccharide of the lambda-carrageenan ideal structure with galactose 2,6-disulfate at the reducing end, indicating the enzyme cleaves the beta-1,4 linkages of its backbone structure. Furthermore, the gene (cglA) encoding the enzyme was sequenced. It encoded a mature protein of 103 kDa (917 amino acids). Remarkably, the deduced amino acid sequence showed no similarity to any reported proteins.

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Carbohydrates / chemistry
  • Carrageenan / metabolism*
  • Enzyme Stability
  • Geologic Sediments / microbiology
  • Glycoside Hydrolases / genetics
  • Glycoside Hydrolases / isolation & purification
  • Glycoside Hydrolases / metabolism*
  • Hydrogen-Ion Concentration
  • Hydrolysis
  • Molecular Sequence Data
  • Pseudoalteromonas / enzymology*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Substrate Specificity
  • Temperature


  • Bacterial Proteins
  • Carbohydrates
  • Recombinant Proteins
  • Carrageenan
  • Glycoside Hydrolases
  • lambda-carrageenase, Pseudoalteromonas