Stability of native and cross-linked crystalline glucose isomerase

✍ Scribed by Kalevi Visuri; Ossi Pastinen; Xiaoyan Wu; Kristiina Mäkinen; Matti Leisola

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 124 KB
• Volume: 64
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/(sici)1097-0290(19990805)64:3<377::aid-bit15>3.0.co;2-c

✦ Synopsis

Stabilities of native and cross-linked crystalline forms of Streptomyces rubiginosus glucose isomerase were compared in buffer and in 45% glucose/fructose solutions. The cross-linked crystalline form of the enzyme was more stable in the presence of substrate while in a buffer solution the native enzyme was more stable. Inactivation of native enzyme in buffer did not obey firstorder kinetics but proceeded with a rapid first phase followed by a stable phase. This stabilization is interpreted to be a result of a conformational change in the protein structure. Inactivation of the native enzyme in buffer was directly related to protein precipitation. In the presence of high substrate concentration, the inactivation was related to browning reactions between the enzyme and the reactive sugar, resulting in soluble sugar-protein complexes.