Identification of Essential Ionizable Groups in Active Site ofAspergillus niger α-Glucosidase

A Catalytic Amino Acid and Primary Structure of Active Site inAspevgillus nigerα-Glucosidase

“…The pKANGase of reactive amino acid residue in inactivation by CBE was almost the same as pKe l for the ionizable group 1 in acidic side. In the previous kinetic studies, 3) the ionizable group 1 was identified as a dissociated carboxyl group (-COO -), which was directly involved in the catalytic reaction, implying that the carboxylate group in the active site of ANGase might be modified by CBE.…”

Structure of the Sulfolobus solfataricus α-Glucosidase: Implications for Domain Conservation and Substrate Recognition in GH31

“…Two aspartic acid residues have been identified as the catalytic nucleophile and the acid/base, respectively. 3,19,[26][27][28][29][30] The region surrounding the catalytic nucleophile is highly conserved in the family and constitutes one of the two signature motifs of GH31 (PROSITE consensus motifs PS00129 and PS00707). Genome sequencing projects have revealed a number of putative bacterial gene products that could be assigned to GH31.…”

Synthesis of Isomalto-Oligosaccharides by Pichia pastoris Displaying the Aspergillus niger α-Glucosidase

“…The optimal pH of the activity of Pp-ANGL-GCW61 is from 3.0–4.0, while the optimal pH is from 5.0–6.0 for transglucosidase L (Amano Enzymes Inc., Japan). These changes in the optimal pH range have rarely been reported by other researchers. − The essential ionizable groups of the α-glucosidase are two kinds of carboxyl groups: one is charged, and the other is a protonated . One possible reason for this behavior was that the GPI-modified cell-wall protein (GCW), which was coexpressed with ANGL, influenced the three-dimensional structure and the charge of the enzyme.…”

“…18−20 The essential ionizable groups of the α-glucosidase are two kinds of carboxyl groups: one is charged, and the other is a protonated. 27 One possible reason for this behavior was that the GPI-modified cell-wall protein (GCW), which was coexpressed with ANGL, influenced the three-dimensional structure and the charge of the enzyme. We also studied the relationship between pH and stability of Pp-ANGL-GCW61.…”