title: Multi-functional roles of a histidine residue in human pancreatic alpha-amylase.
abstract: Functional roles of histidine residues at the active site in human pancreatic alpha-amylase were examined by protein engineering. Three histidine residues at 101, 201, and 299 were converted to asparagine residues, respectively. It was found that His201 played multi-functional roles concerning so many functions; substrate binding, control of optimum pH, change in substrate specificity, activation by chloride ion, and inhibition by a proteinaceous inhibitor.
authors.affiliation: National Chemical Laboratory for Industry, Ibaraki, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ishikawa
authors.forename: I
authors.initials: I
authors.lastname: Matsui
authors.forename: K
authors.initials: K
authors.lastname: Honda
authors.forename: H
authors.initials: H
authors.lastname: Nakatani
mesh_terms: D001665:Binding Sites; D006639:Histidine / Q000235:genetics; D006801:Humans; D016297:Mutagenesis, Site-Directed; D010179:Pancreas / Q000201:enzymology*; D015202:Protein Engineering; D013329:Structure-Activity Relationship; D000516:alpha-Amylases / Q000235:genetics*
chemical_list: D006639:Histidine; D000516:alpha-Amylases