Affiliation:
1. Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, D.F., México
Abstract
Abstract
Isocitrate dehydrogenase is a key enzyme in carbon metabolism. In this study we demonstrated that SCO7000 of Streptomyces coelicolor M-145 codes for the isocitrate dehydrogenase. Recombinant enzyme expressed in Escherichia coli had a specific activity of 25.3 μmoles/mg/min using NADP+ and Mn2+ as a cofactor, 40-times higher than that obtained in cell-free extract. Pure IDH showed a single band with an apparent Mr of 84 KDa in SDS-PAGE, which was also recognized as His-tag protein in the Western blot. Unexpectedly, in ND-PAGE conditions showed a predominant band of ~168 KDa that corresponded to the dimeric form of ScIDH. Also, zymogram assay and analytical gel filtration reveal that dimer was the active form. Kinetic parameters were 1.38, 0.11, and 0.109 mM for isocitrate, NADP, and Mn2+, respectively. ATP, ADP, AMP, and their mixtures were the main ScIDH activity inhibitors. Zn2+, Mg2+, Ca2+, and Cu+ had inhibitory effect on enzyme activity.
Publisher
Oxford University Press (OUP)
Subject
Organic Chemistry,Molecular Biology,Applied Microbiology and Biotechnology,General Medicine,Biochemistry,Analytical Chemistry,Biotechnology
Cited by
2 articles.
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