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Kanpiengjai, A; Nguyen, TH; Haltrich, D; Khanongnuch, C.
(2017): Expression and comparative characterization of complete and C-terminally truncated forms of saccharifying alpha-amylase from Lactobacillus plantarum S21
INT J BIOL MACROMOL. 2017; 103: 1294-1301. FullText FullText_BOKU

Lactobacillus plantarum S21 alpha-amylase possesses 475 amino acids at the C-terminal region identified as the starch-binding domain (SBD) and has been previously reported to play a role in raw starch degradation. To understand the specific roles of this SBD, cloning and expression of the complete (AmyL9) and C-terminally truncated (AmyL9 Delta(SBD)) forms of alpha-amylase were conducted for enzyme purification and comparative characterization. AmyL9 and AmyL9 Delta(SBD) were overproduced in Escherichia coli at approximately 10- and 20-times increased values of volumetric productivity when compared to alpha-amylase produced by the wild type, respectively. AmyL9 Delta(SBD) was unable to hydrolyze raw starch and exhibited substrate specificity in a similar manner to that of AmyL9, but it was weakly active toward amylopectin and glycogen. The hydrolysis products obtained from the amylaceous substrates of both enzymes were the same. In addition, AmyL9 Delta(SBD) showed comparatively higher K-m values than AmyL9 when it reacted with starch and amylopectin, and lower values for other kinetic constants namely v(max), k(cat), and k(cat)/K-m. The results indicated that the C-terminal SBDs of L. plantarum S21 alpha-amylase contribute to not only substrate preference but also substrate affinity and the catalytic efficiency of the alpha-amylase without any changes in the degradation mechanisms of the enzyme. (C) 2017 Elsevier B.V. All rights reserved.
Authors BOKU Wien:
Haltrich Dietmar
Nguyen Thu Ha

Find related publications in this database (Keywords)
C-terminal truncation
Starch-binding domain
Raw starch

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