کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10771427 1050841 2005 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Bifunctional isocitrate-homoisocitrate dehydrogenase: A missing link in the evolution of β-decarboxylating dehydrogenase
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شیمی
پیش نمایش صفحه اول مقاله
Bifunctional isocitrate-homoisocitrate dehydrogenase: A missing link in the evolution of β-decarboxylating dehydrogenase
چکیده انگلیسی
β-Decarboxylating dehydrogenases comprise 3-isopropylmalate dehydrogenase, isocitrate dehydrogenase, and homoisocitrate dehydrogenase. They share a high degree of amino acid sequence identity and occupy equivalent positions in the amino acid biosynthetic pathways for leucine, glutamate, and lysine, respectively. Therefore, not only the enzymes but also the whole pathways should have evolved from a common ancestral pathway. In Pyrococcus horikoshii, only one pathway of the three has been identified in the genomic sequence, and PH1722 is the sole β-decarboxylating dehydrogenase gene. The organism does not require leucine, glutamate, or lysine for growth; the single pathway might play multiple (i.e., ancestral) roles in amino acid biosynthesis. The PH1722 gene was cloned and expressed in Escherichia coli and the substrate specificity of the recombinant enzyme was investigated. It exhibited activities on isocitrate and homoisocitrate at near equal efficiency, but not on 3-isopropylmalate. PH1722 is thus a novel, bifunctional β-decarboxylating dehydrogenase, which likely plays a dual role in glutamate and lysine biosynthesis in vivo.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochemical and Biophysical Research Communications - Volume 331, Issue 1, 27 May 2005, Pages 341-346
نویسندگان
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