title: Chemical modification of Saccharomycopsis fibuligera R64 α-amylase to improve its stability against thermal, chelator, and proteolytic inactivation.
abstract: α-Amylase catalyzes hydrolysis of starch to oligosaccharides, which are further degraded to simple sugars. The enzyme has been widely used in food and textile industries and recently, in generation of renewable energy. An α-amylase from yeast Saccharomycopsis fibuligera R64 (Sfamy) is active at 50 °C and capable of degrading raw starch, making it attractive for the aforementioned applications. To improve its characteristics as well as to provide information for structural study ab initio, the enzyme was chemically modified by acid anhydrides (nonpolar groups), glyoxylic acid (GA) (polar group), dimethyl adipimidate (DMA) (cross-linking), and polyethylene glycol (PEG) (hydrophilization). Introduction of nonpolar groups increased enzyme stability up to 18 times, while modification by a cross-linking agent resulted in protection of the calcium ion, which is essential for enzyme activity and integrity. The hydrophilization with PEG resulted in protection against tryptic digestion. The chemical modification of Sfamy by various modifiers has thereby resulted in improvement of its characteristics and provided systematic information beneficial for structural study of the enzyme. An in silico structural study of the enzyme improved the interpretation of the results.
authors.affiliation: Biochemistry Laboratory, Department of Chemistry, Faculty of Mathematics and Natural Sciences, Padjadjaran University, Jalan Singaperbangsa No. 2, 40133 Bandung, Indonesia. wangsatirta@gmail.com
authors.forename: Wangsa Tirta
authors.initials: WT
authors.lastname: Ismaya
authors.forename: Khomaini
authors.initials: K
authors.lastname: Hasan
authors.forename: Idar
authors.initials: I
authors.lastname: Kardi
authors.forename: Amalia
authors.initials: A
authors.lastname: Zainuri
authors.forename: Rinrin Irma
authors.initials: RI
authors.lastname: Rahmawaty
authors.forename: Satyawisnu
authors.initials: S
authors.lastname: Permanahadi
authors.forename: Baiq Vera
authors.initials: BV
authors.lastname: El Viera
authors.forename: Gunawan
authors.initials: G
authors.lastname: Harinanto
authors.forename: Shabarni
authors.initials: S
authors.lastname: Gaffar
authors.forename: Dessy
authors.initials: D
authors.lastname: Natalia
authors.forename: Toto
authors.initials: T
authors.lastname: Subroto
authors.forename: Soetijoso
authors.initials: S
authors.lastname: Soemitro
mesh_terms: D000089:Acetic Anhydrides / Q000737:chemistry; D000595:Amino Acid Sequence; D002614:Chelating Agents / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D004119:Dimethyl Adipimidate / Q000737:chemistry; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry*; D006038:Glyoxylates / Q000737:chemistry; D006358:Hot Temperature; D006868:Hydrolysis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011092:Polyethylene Glycols / Q000737:chemistry; D015202:Protein Engineering / Q000379:methods*; D059748:Proteolysis; D012442:Saccharomycopsis / Q000737:chemistry* / Q000201:enzymology; D013213:Starch / Q000378:metabolism; D000516:alpha-Amylases / Q000737:chemistry*
chemical_list: D000089:Acetic Anhydrides; D002614:Chelating Agents; D003432:Cross-Linking Reagents; D005656:Fungal Proteins; D006038:Glyoxylates; D004119:Dimethyl Adipimidate; D011092:Polyethylene Glycols; D013213:Starch; D000516:alpha-Amylases; C031150:glyoxylic acid