Molecular cloning and expression in S. cerevisiae of two exochitinases from Trichoderma harzianum

Biochem Mol Biol Int. 1995 Jul;36(4):781-91.


The synthetic exochitinase substrate 4-methylumbelliferyl N-acetylglucosamine was used to identify seven full-length exochitinase-encoding cDNAs from a Trichoderma harzianum cDNA library by expression in yeast. The cDNA clones represented transcripts of two exochitinase genes, designated as exc1 and exc2, which cross-hybridized under moderate stringency conditions in genomic Southern blots. The exc1 cDNA encodes a 578 amino acid polypeptide showing 72% similarity to the exc2-encoded 602-residue polypeptide. The deduced exochitinase amino acid sequences were found to be homologous with mammalian and fungal hexosaminidases as well as a bacterial chitobiosidase. The substrate specificity of the recombinant enzymes expressed in S. cerevisiae indicates that the enzymes are N-acetylglucosaminidases releasing single N-acetylglucosamine residues from the non-reducing end of the chitin substrate.

Publication types

  • Comparative Study

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Blotting, Southern
  • Cloning, Molecular / methods
  • DNA, Complementary
  • Dictyostelium / enzymology
  • Fungal Proteins*
  • Gene Expression
  • Gene Library
  • Genes, Fungal
  • Hexosaminidases / biosynthesis*
  • Hexosaminidases / chemistry
  • Hexosaminidases / genetics
  • Humans
  • Molecular Sequence Data
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Saccharomyces cerevisiae
  • Sequence Homology, Amino Acid
  • Transcription, Genetic
  • Trichoderma / enzymology*
  • Trichoderma / genetics


  • DNA, Complementary
  • Fungal Proteins
  • Recombinant Proteins
  • Exc1 protein, Trichoderma harzianum
  • Exc2 protein, Trichoderma harzianum
  • Hexosaminidases