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Amino acid substitutions of the limit dextrinase gene in barley are associated with the enzyme thermostability


Yang, X and Westcott, S and Gong, X and Evans, E and Zhang, XQ and Lance, RCM and Li, C, Amino acid substitutions of the limit dextrinase gene in barley are associated with the enzyme thermostability, Molecular Breeding, 23, (1) pp. 61-74. ISSN 1380-3743 (2009) [Refereed Article]

DOI: doi:10.1007/s11032-008-9214-2


Limit dextrinase (LD) is a key enzyme in determining the malting quality. A survey of 60 barley varieties showed a wide range of variation for the enzyme activity and thermostability. Galleon showed low enzyme activity and high thermostability while Maud showed high activity and low thermostability. Alignment of the LD amino acid sequences of Galleon and Maud identified seven amino acid substitutions Lys/Arg-102, Thr/Ala-233, Ser/Gly-235, Gly/Ala-298, Cys/Arg-415, Ala/Ser-885 and Gly/Cys-888. Genetic diversity of LD was investigated using single strand conformation polymorphism based on the amino acid substitutions. Only limited genetic variation was detected in the current malting barley varieties, although wide variation was observed in the wider barley germplasm. The Thr/Ala-233 and Ala/Ser-885 substitutions were associated with enzyme thermostability ( < 0.0001), but no polymorphism was associated with the enzyme activity. This result was confirmed from further sequence analysis. The results will provide a tool for understanding and selection of high LD thermostability.

Item Details

Item Type:Refereed Article
Research Division:Agricultural, Veterinary and Food 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:Grains and seeds
Objective Field:Barley
UTAS Author:Evans, E (Dr Evan Evans)
ID Code:44456
Year Published:2009
Web of Science® Times Cited:12
Deposited By:Agricultural Science
Deposited On:2008-08-01
Last Modified:2013-01-31

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