A Solanum tuberosum inositol phosphate kinase (StITPK1) displaying inositol phosphate-inositol phosphate and inositol phosphate-ADP phosphotransferase activities
A Solanum tuberosum inositol phosphate kinase (StITPK1) displaying inositol phosphate-inositol phosphate and inositol phosphate-ADP phosphotransferase activities
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DOI：
10.1016/j.febslet.2008.04.034
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发表时间：
2008-05-28
期刊：
影响因子：
3.5
通讯作者：
Brearley, Charles A.
中科院分区：
文献类型：
--
作者：
Caddick, Samuel E. K.;Harrison, Christopher J.;Brearley, Charles A.
我们描述了一种来自龙葵的多功能肌醇多磷酸激酶/磷酸转移酶，StITPK α (GenBank登录：EF362784)，以下称为StITPK1。StITPK1显示肌醇3,4,5,6-四磷酸1-激酶活性：K-m = 27 μ M, V-max = 19 nmol min(-1) mg（-1）。该酶在缺乏核苷酸受体时显示肌醇1,3,4,5,6-五戊磷酸1-磷酸酶活性，在存在生理浓度的ADP时显示肌醇1,3,4,5,6-五戊磷酸-ADP磷酸转移酶活性。此外，StITPK1显示肌醇磷酸-肌醇磷酸转移酶活性。同源性建模提供了stipk1催化能力的结构原理。磷酸肌醇之间的磷酸基团在底物间转移是这类酶进化上保守的功能。(C) 2008年欧洲生化学会联合会。版权所有。
We describe a multifunctional inositol polyphosphate kinase/phosphotransferase from Solanum tuberosum, StITPK alpha (GenBank accession: EF362784), hereafter called StITPK1. StITPK1 displays inositol 3,4,5,6-tetrakisphosphate 1-kinase activity: K-m = 27 mu M, and V-max = 19 nmol min(-1) mg(-1). The enzyme displays inositol 1,3,4,5,6-pentakisphosphate 1-phosphatase activity in the absence of a nucleotide acceptor and inositol 1,3,4,5,6-pentakisphosphate-ADP phosphotransferase activity in the presence of physiological concentrations of ADP. Additionally, StITPK1 shows inositol phosphate-inositol phosphate phosphotransferase activity. Homology modelling provides a structural rationale of the catalytic abilities of StITPK1. Inter-substrate transfer of phosphate groups between inositol phosphates is an evolutionarily conserved function of enzymes of this class. (C) 2008 Federation of European Biochemical Societies. All rights reserved.