endo-β-1,4-Mannanases from blue mussel, Mytilus edulis: purification, characterization, and mode of action

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Abstract

Two variants of an endo-β-1,4-mannanase from the digestive tract of blue mussel, Mytilus edulis, were purified by a combination of immobilized metal ion affinity chromatography, size exclusion chromatography in the absence and presence of guanidine hydrochloride and ion exchange chromatography. The purified enzymes were characterized with regard to enzymatic properties, molecular weight, isoelectric point, amino acid composition and N-terminal sequence. They are monomeric proteins with molecular masses of 39&#;216 and 39&#;265 Da, respectively, as measured by MALDI-TOF mass spectrometry. The isoelectric points of both enzymes were estimated to be around 7.8, however slightly different, by isoelectric focusing in polyacrylamide gel. The enzymes are stable from pH 4.0 to 9.0 and have their maximum activities at a pH about 5.2. The optimum temperature of both enzymes is around 50-55oC. Their stability decreases rapidly when going from 40 to 50oC. The N-terminal sequences (12 residues) were identical for the two variants. They can be completely renatured after denaturation in 6 M guanidine hydrochloride. The enzymes readily degrade the galactomannans from locust bean gum and ivory nut mannan but show no cross-specificity for xylan and carboxymethyl cellulose. There is no binding ability observed towards cellulose and mannan

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Subject classification (UKÄ) – MANDATORY

  • Biological Sciences

Keywords

  • Mytilus edulis, Blue mussel, Purification, β-Mannanase
Original languageEnglish
Pages (from-to)267-277
JournalJournal of Biotechnology
Volume92
Issue number3
Publication statusPublished - 2002
Publication categoryResearch
Peer-reviewedYes