Extracellular proteolytic processing ofAspergillus awamori GAI into GAII is supported by physico-chemical evidence

  • Hilton J. Nascimento
  • Valeria F. Soares
  • Elba P. S. Bon
  • José G. Silva
Session 3: Bioprocessing Research


The proportion of glucoamylases, GAI and GAII, in the culture supernatant ofAspergillus awamori fermentations depends on the medium C/N ratio in such a way that the transformation of GAI into GAII is favored by the existence of a surplus of the carbon source in the growth medium. This condition also favors the appearance of the proteolytic activity. The authors report the observation that the shift in the isoenzyme proportion was concomitant to the peak of proteolytic activity. A peptide that may have resulted from the continuous degradation of the GAI C-terminal peptide, Gp-1, was isolated by gel filtration and purified by reversephase chromatography. This peptide matched with the region G14-A34 of the substrate-binding domain of GAI, thus reinforcing the hypothesis of the extracellular proteolytic processing of GAI.

Index Entries

Aspergillus awamori glucoamylase GAI and GAII glu-coamylase isoenzymes processing isoenzymes extracellular processing isoenzymes proteolytic processing 


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Copyright information

© Humana Press Inc. 1998

Authors and Affiliations

  • Hilton J. Nascimento
    • 1
  • Valeria F. Soares
    • 1
  • Elba P. S. Bon
    • 1
  • José G. Silva
    • 1
  1. 1.Instituto de QuímicaUniversidade Federal do Rio de JaneiroRio de Janeiro, RJBrasil

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