Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8329090 | International Journal of Biological Macromolecules | 2017 | 6 Pages |
Abstract
γ-Glutamyltranspeptidase (GGT) is a dimeric protein that specifically catalyzes the transfer of γ-glutamyl in the optimum pH range of 8.5-9.0, but has poor in vitro stability under the alkaline conditions. In the present work, GGT was immobilized on a mesoporoustitania oxide whisker (MTWs) carrier to afford MTWs-GGT that was further modified with PharmalyteMT (Phar) 8.0-10.5 to yield MTWs-GGT-Phar. Phar absorbed on MTWs-GGT to form a buffering layer with an isoelectric point of â¼9.2 that isolated the immobilized enzyme from the liquid bulk and significantly in proved the pH tolerance and stability of the immobilized GGT. The MTWs-GGT-Phar exhibited a stable enzyme activity in the pH range of 6.0-11.0 and an optimum temperature 10 °C higher than GGT. Its pH stability at pH 11.0 and thermal stability at 50 °C were respectively 23.7 times and 19.4 times higher than those of GGT. In addition, the affinity constant of MTWs-GGT-Phar towards GpNA (Km) was 0.597 mM, slightly lower than that of free GGT, indicating that Phar had a protective effect on the structure of GGT.
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Authors
Fang Ni, Fan Zhang, Zhong Yao, Lijing Ye, Yun Sun, Haoqi Wang, Zhi Zhou, Benwei Zhu,