The 1,4-beta-D-glucan glucanohydrolases from Phanerochaete chrysosporium. Re-assessment of their significance in cellulose degradation mechanisms

J Biotechnol. 1991 Nov;21(1-2):143-59. doi: 10.1016/0168-1656(91)90267-y.

Abstract

A physico-chemical, functional and structural characterization, including partial sequence data, of three major 1,4-beta-D-glucan glucanohydrolases (EC. 3.2.1.4) isolated from the culture filtrate of the white-rot fungus Phanerochaete chrysosporium, shows that all three enzymes belong to a single family of cellulases. EG44, pI 4.3, (named after its apparent molecular mass in kDa), shows a clear homology with Schizopyllum commune Endoglucanase I (EGI); whereas EG38, pI 4.9, (named in the same manner) is related more closely to Trichoderma reesei (Trichoderma longibrachiatum) Endoglucanase III (EGIII). EG36, pI 5.6-5.7, is probably an EG38 protein lacking its cellulose binding domain. Strong synergistic action is induced by the enzymes acting in concert with cellobiohydrolases (CBHI and CBHII) from the same organism, indicating a highly effective enzymatic system for cellulose degradation. Controlled proteolysis with papain has allowed a so far unique cleavage of endoglucanases EG44 and EG38 into two domains: a core protein, which virtually lacks the capacity to absorb onto microcrystal-line cellulose but retains full catalytic activity against carboxymethyl cellulose and low molecular weight soluble substrates; and a peptide fragment corresponding to the cellulose binding domain. The latter appears to be of paramount significance in the mechanisms involved in the hydrolysis of microcrystalline cellulose.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / analysis
  • Basidiomycota / enzymology*
  • Cellulase / analysis*
  • Cellulose / metabolism*
  • Molecular Sequence Data
  • Trichoderma / enzymology

Substances

  • Amino Acids
  • Cellulose
  • Cellulase