title: Thermostabilization of Bacillus amyloliquefaciens alpha-amylase by chemical cross-linking.
abstract: Chemical cross-linking of a mesophilic alpha-amylase from Bacillus amyloliquefaciens (BAA) was carried out. Intra-molecular cross-links between lysine residues upon treatment of the enzyme with ethylene glycol bis(succinic acid N-hydroxy succinimide ester) resulted in enhancement of thermostability as indicated by irreversible thermoinactivation experiments. Enhancement of thermostability coincided with a dramatic protection against aggregation, combined with a decrease in surface hydrophobicity. Deamidation, another important mechanism of irreversible thermoinactivation, was also diminished upon modification. While no significant changes in the kinetic parameters are evident, rigidification of the protein structure is suggested by circular dichroism (CD) and fluorescence studies.
authors.affiliation: Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box 13145-1384, Tehran, Iran.
authors.forename: Azadeh Ebrahim
authors.initials: AE
authors.lastname: Habibi
authors.forename: Khosro
authors.initials: K
authors.lastname: Khajeh
authors.forename: Hossein
authors.initials: H
authors.lastname: Naderi-Manesh
authors.forename: Bijan
authors.initials: B
authors.lastname: Ranjbar
authors.forename: Mohsen
authors.initials: M
authors.lastname: Nemat-Gorgani
mesh_terms: D001407:Bacillus / Q000201:enzymology*; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000494:pharmacology*; D004795:Enzyme Stability / Q000187:drug effects; D006358:Hot Temperature; D008239:Lysine / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D000516:alpha-Amylases / Q000737:chemistry*
chemical_list: D003432:Cross-Linking Reagents; D000516:alpha-Amylases; D008239:Lysine