Serratia marcescens chitobiase is a retaining glycosidase utilizing substrate acetamido group participation

S Drouillard, S Armand, G J Davies, C E Vorgias, B Henrissat

Research output: Contribution to journalArticlepeer-review

Abstract

The stereochemistry of the reaction catalysed by Serratia marcescens chitobiase was determined by HPLC separation of the anomers of N-acetylglucosamine produced during the hydrolysis of p-nitrophenyl N-acetyl-beta-D-glucosaminide (PNP-GlcNAc). In the early stages of the reaction, the beta-anomer was found to prevail, whereas the alpha-anomer dominated at mutarotation equilibrium. This established that chitobiase hydrolyses glycosidic bonds with overall retention of the anomeric configuration. Chitobiase-catalysed hydrolysis of PNP-GlcNAc was competitively inhibited by a series of chito-oligosaccharides (degree of polymerization 2-5) that were selectively de-N-acetylated at their non-reducing end. The results are in accord with the participation of the acetamido group at C-2 of the substrate in the catalytic mechanism of chitobiase and related enzymes.

Original languageEnglish
Pages (from-to)945-949
Number of pages5
JournalBiochemical journal
Volume328
Publication statusPublished - 15 Dec 1997

Keywords

  • EGG-WHITE LYSOZYME
  • GLYCOSYL HYDROLASES
  • CRYSTAL-STRUCTURE
  • CHITINASE
  • HYDROLYSIS
  • MECHANISMS
  • STEREOCHEMISTRY
  • INHIBITOR
  • SEQUENCE
  • COMPLEX

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