A novel thermophilic exochitinase ChiEn3 from Coprinopsis cinerea exhibits a hyperhydrolytic activity toward 85% deacetylated chitosan and a significant application to preparation of chitooligosaccharides from the chitosan

Carbohydr Polym. 2019 Mar 1:207:729-736. doi: 10.1016/j.carbpol.2018.12.047. Epub 2018 Dec 17.

Abstract

ChiEn3 from Coprinopsis cinerea was characterized as an exo-acting chitinase with a processivity. ChiEn3 hydrolyzed only soluble chitin and exhibited a hyperhydrolytic activity toward 85% deacetylated chitosan which was 33.6-fold higher than its hydrolytic activity toward glycol chitin. Its maximum hydrolytic activity was observed at 60 °C and retained 66.2% of hydrolytic activity after 60 min incubation at 60 °C. Commercial 85% deacetylated chitosan was degraded by ChiEn3 to a series of COSs with a DP of 2-20 in which COSs with a DP of 3-6 were dominant, whereas, lab-prepared chitosan (FA = 0.65) was degraded by ChiEn3 to COSs with a DP of 2-10 in which the AA dimer was dominant. DPPH-radical-scavenging activity of ChiEn3-digested products of 85% deacetylated chitosan was 3.32-fold higher than that of undigested 85% deacetylated chitosan. Therefore, ChiEn3 shows a valuable advantage for application to the preparation of COSs from commercial 85% deacetylated chitosan.

Keywords: 85% deacetylated chitosan; Anti-oxidant activity; Chitooligosaccharides; Exochitinase; Thermophilicity.

MeSH terms

  • Agaricales / enzymology*
  • Amino Acid Sequence
  • Antioxidants / chemical synthesis
  • Antioxidants / chemistry
  • Base Sequence
  • Chitin / analogs & derivatives
  • Chitin / chemical synthesis
  • Chitin / chemistry
  • Chitinases / chemistry*
  • Chitinases / isolation & purification
  • Chitosan / chemistry*
  • Fungal Proteins / chemistry*
  • Fungal Proteins / isolation & purification
  • Hydrolysis
  • Oligosaccharides
  • Protein Conformation

Substances

  • Antioxidants
  • Fungal Proteins
  • Oligosaccharides
  • oligochitosan
  • Chitin
  • Chitosan
  • Chitinases