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Removal of the four C-terminal glycine rich repeats enhances the thermostability of barley β-amylase

Citation

Ma, YF and Eglinton, JK and Evans, DE and Logue, SJ and Langridge, P, Removal of the four C-terminal glycine rich repeats enhances the thermostability of barley β-amylase, Biochemistry, 39 pp. 13350-13355. ISSN 0006-2960 (2000) [Refereed Article]

DOI: doi:10.1021/bi000688s

Abstract

Barley β-amylase undergoes proteolytic cleavage in the C-terminal region after germination. The implication of the cleavage in the enzyme's characteristics is unclear. With purified native β-amylases from both mature barley grain and germinated barley, we found that the β-amylase from germinated barley had significantly higher thermostability and substrate binding affinity for starch than that from mature barley grain. To better understand the effect of the proteolytic cleavage on the enzyme's thermostability and substrate binding affinity for starch, recombinant barley β-amylases with specific deletions at the C-terminal tail were generated. The complete deletion of the four C-terminal glycine-rich repeats significantly increased the enzyme's thermostability, but an incomplete deletion with one repeat remaining did not change the thermostability. Although different C-terminal deletions affect the thermostability differently, they all increased the enzyme's affinity for starch. The possible reasons for the increased thermostability and substrate binding affinity, due to the removal of the four C-terminal glycine-rich repeats, are discussed in terms of the three-dimensional structure of β-amylase.

Item Details

Item Type:Refereed Article
Research Division:Agricultural and Veterinary Sciences
Research Group:Crop and Pasture Production
Research Field:Crop and Pasture Biochemistry and Physiology
Objective Division:Plant Production and Plant Primary Products
Objective Group:Winter Grains and Oilseeds
Objective Field:Barley
Author:Evans, DE (Dr David Evans)
ID Code:34044
Year Published:2000
Web of Science® Times Cited:22
Deposited By:Agricultural Science
Deposited On:2005-07-23
Last Modified:2005-07-23
Downloads:0

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