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Title: Interaction of wheat β-amylase with maltose and glucose as examined by fluorescence.
Authors: Daba, Tadessa
Kojima, Kenji  kyouindb  KAKEN_id
Inouye, Kuniyo
Author's alias: 井上, 國世
Keywords: dissociation constant
fluorescence quenching
glucose
maltose
wheat β-amylase
Issue Date: Jul-2013
Publisher: Oxford University Press
Journal title: Journal of biochemistry
Volume: 154
Issue: 1
Start page: 85
End page: 92
Abstract: Fluorescence of wheat β-amylase (WBA) was quenched by the interaction with maltose or glucose, which are competitive inhibitors of WBA, suggesting that the states of tryptophan and tyrosine residues could be changed by the interaction. The fluorescence emitted by excitation at 280 and 295 nm was titrated by changing the concentrations of maltose and glucose. The dissociation constant (Kd) values of the WBA-maltose and WBA-glucose complexes were determined to be 0.20 ± 0.12 M for maltose and 0.36 ± 0.11 M for glucose at 25°C, pH 5.4. Maltose exhibited additional binding mode at higher concentration with a distinct Kd value (1.5 ± 0.4 M). The Kd values at various temperatures and pHs are in agreement with the inhibitor constant (Ki) values previously reported. The negative standard enthalpy changes (ΔH°) of the WBA association with glucose and maltose indicate that the associations are exothermic. The association constant (Ka) and ΔG° values of the maltose and glucose binding to WBA decreased slightly with increasing temperature from 25°C to 45°C but not dependent on pH change (pH 3.0, 5.4 and 9.0). Fluorescence of WBA could be used as a structural probe to examine the inhibitory interaction with the products of starch hydrolysis.
Rights: This is a pre-copyedited, author-produced PDF of an article accepted for publication in "Journal of Biochemistry" following peer review. The version of record "Tadessa Daba, Kenji Kojima, and Kuniyo Inouye; Interaction of wheat β-amylase with maltose and glucose as examined by fluorescence; J Biochem (2013) 154 (1): 85-92 first published online April 16, 2013 doi:10.1093/jb/mvt029" is available online at:http://jb.oxfordjournals.org/content/154/1/85
This is not the published version. Please cite only the published version. この論文は出版社版でありません。引用の際には出版社版をご確認ご利用ください。
URI: http://hdl.handle.net/2433/189714
DOI(Published Version): 10.1093/jb/mvt029
PubMed ID: 23596054
Appears in Collections:Journal Articles

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