Abstract:

Exo-inulinase and endo-inulinase from Aspergillus ficuum were subject to chemical modification of seven protein modification reagents and to identification of amino acid residues essential for enzyme activity. The results suggested that Nbromosuccinimide (NBS), carbodiimide (EDC) and diethyl pyrocarbonate (DEPC) resulted in a great loss of endo- and exoinulinase activities, indicating that Trp, carboxyl amino acid (Glu or Asp) and His residues may be parts of the enzyme active sites, respectively. Two Trp residues essential for exo-inulinase active site and one for endo-inulinase were confirmed by Tsou’s method.

Key words: Aspergillus ficuum, inulinase, chemical modification, active site