Abstrak 
Chemical Modification of Saccharomycopsis fibuligera R64 α-Amylase to Improve its Stability Against Thermal, Chelator, and Proteolytic Inactivation
Wangsa Tirta Ismaya, Khomaini Hasan, Idar Kardi, Amalia Zainuri, Rinrin Irma Rahmawaty, Satyawisnu Permanahadi, Baiq Vera El Viera, Gunawan Harinanto, Shabarni Gaffar, Dessy Natalia, Toto Subroto, Soetijoso Soemitro
Universitas Padjadjaran, Springer Science+Business Received: 28 November 2011 / Accepted: 21 February 2013 Media New York 2013 Applied Biochemistry and Biotechnology Part A: Enzyme Engineering and Biotechnology ISSN 0273-2289 Appl Biochem Biotechnol DOI 10.1007/s12010-013-0164-8
Bahasa Inggris
Universitas Padjadjaran, Springer Science+Business Received: 28 November 2011 / Accepted: 21 February 2013 Media New York 2013 Applied Biochemistry and Biotechnology Part A: Enzyme Engineering and Biotechnology ISSN 0273-2289 Appl Biochem Biotechnol DOI 10.1007/s12010-013-0164-8
Chemical modification, Enzyme engineering, modification, Saccharomycopsis fibuligera, Structure–function relationship, Tryptic digestion, α–Amylase
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 a-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.