期刊
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
卷 451, 期 4, 页码 541-547出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.bbrc.2014.08.019
关键词
Bacillus licheniformis thermostable; alpha-amylase; Substrate transglycosylation; Site-directed mutagenesis; Transfer product; Binding-subsite mapping
资金
- National Research Foundation [2012R1A1A2005012]
- Next Generation BioGreen21 Program (SSAC) [PJ009086]
- Rural Development Administration, Republic of Korea
- National Research Foundation of Korea [2012R1A1A2005012] Funding Source: Korea Institute of Science & Technology Information (KISTI), National Science & Technology Information Service (NTIS)
To understand the role of His and Glu in the catalytic activity of Bacillus licheniformis a-amylase (BLA), His235 was replaced with Glu. The mutant enzyme, H235E, was characterized in terms of its mode of action using labeled and unlabeled maltooctaose (Glc8). H235E predominantly produced maltotridecaose (Glc13) from Glc8, exhibiting high substrate transglycosylation activity, with K-m = 0.38 mM and k(cat)/K-m = 20.58 mM(-1) s(-1) for hydrolysis, and K-m2 = 18.38 mM and k(cat2)/K-m2 = 2.57 mM(-1) s(-1) for transglycosylation, while the wild-type BLA exhibited high hydrolysis activity exclusively. Glu235-located on a wide open groove near subsite +1-is likely involved in transglycosylation via formation of an alpha-1,4-glycosidic linkage and may recognize and stabilize the non-reducing end glucose of the acceptor molecule. (C) 2014 Elsevier Inc. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据