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Isocitrate dehydrogenase kinase/phosphatase.
Biochimie. 1989 Sep-Oct; 71(9-10):1051-7.B

Abstract

In Escherichia coli, isocitrate dehydrogenase (IDH) is regulated by phosphorylation. This phosphorylation cycle is catalyzed by an unusual, bifunctional protein:IDH kinase/phosphatase. IDH kinase/phosphatase is expressed from a single gene, aceK, and both activities are catalyzed by the same polypeptide. The amino acid sequence of IDH kinase/phosphatase does not exhibit the characteristics which are typical of other protein kinases, although it does contain a consensus ATP binding site. The available evidence suggests that the IDH kinase and IDH phosphatase reactions occur at the same active site and that the IDH phosphatase reaction results from the back reaction of IDH kinase tightly coupled to ATP hydrolysis. The function of the IDH phosphorylation cycle is to control the flux of isocitrate through the glyoxylate bypass. This pathway is essential for growth on acetate because it prevents the quantitative loss of the acetate carbons as CO2 in the Krebs' cycle. IDH kinase/phosphatase monitors general metabolism by responding to the levels of a wide variety of metabolites, many of which activate IDH phosphatase and inhibit IDH kinase. The ability of IDH kinase/phosphatase to monitor general metabolism allows. the IDH phosphorylation cycle to compensate for substantial perturbations of the system, such as a 15-fold overproduction of IDH. The significance of the cellular level of IDH kinase/phosphatase has also been evaluated. The level of this protein is in great excess of that required for steady-state growth on acetate. In contrast, IDH kinase/phosphatase is, in some cases, rate-limiting for the dephosphorylation of IDH which results when preferred carbon sources are added to cultures growing on acetate.

Authors+Show Affiliations

Department of Biochemistry, University of Minnesota, Minneapolis 55455.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.
Review

Language

eng

PubMed ID

2557093

Citation

Laporte, D C., et al. "Isocitrate Dehydrogenase Kinase/phosphatase." Biochimie, vol. 71, no. 9-10, 1989, pp. 1051-7.
Laporte DC, Stueland CS, Ikeda TP. Isocitrate dehydrogenase kinase/phosphatase. Biochimie. 1989;71(9-10):1051-7.
Laporte, D. C., Stueland, C. S., & Ikeda, T. P. (1989). Isocitrate dehydrogenase kinase/phosphatase. Biochimie, 71(9-10), 1051-7.
Laporte DC, Stueland CS, Ikeda TP. Isocitrate Dehydrogenase Kinase/phosphatase. Biochimie. 1989 Sep-Oct;71(9-10):1051-7. PubMed PMID: 2557093.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Isocitrate dehydrogenase kinase/phosphatase. AU - Laporte,D C, AU - Stueland,C S, AU - Ikeda,T P, PY - 1989/9/1/pubmed PY - 1989/9/1/medline PY - 1989/9/1/entrez SP - 1051 EP - 7 JF - Biochimie JO - Biochimie VL - 71 IS - 9-10 N2 - In Escherichia coli, isocitrate dehydrogenase (IDH) is regulated by phosphorylation. This phosphorylation cycle is catalyzed by an unusual, bifunctional protein:IDH kinase/phosphatase. IDH kinase/phosphatase is expressed from a single gene, aceK, and both activities are catalyzed by the same polypeptide. The amino acid sequence of IDH kinase/phosphatase does not exhibit the characteristics which are typical of other protein kinases, although it does contain a consensus ATP binding site. The available evidence suggests that the IDH kinase and IDH phosphatase reactions occur at the same active site and that the IDH phosphatase reaction results from the back reaction of IDH kinase tightly coupled to ATP hydrolysis. The function of the IDH phosphorylation cycle is to control the flux of isocitrate through the glyoxylate bypass. This pathway is essential for growth on acetate because it prevents the quantitative loss of the acetate carbons as CO2 in the Krebs' cycle. IDH kinase/phosphatase monitors general metabolism by responding to the levels of a wide variety of metabolites, many of which activate IDH phosphatase and inhibit IDH kinase. The ability of IDH kinase/phosphatase to monitor general metabolism allows. the IDH phosphorylation cycle to compensate for substantial perturbations of the system, such as a 15-fold overproduction of IDH. The significance of the cellular level of IDH kinase/phosphatase has also been evaluated. The level of this protein is in great excess of that required for steady-state growth on acetate. In contrast, IDH kinase/phosphatase is, in some cases, rate-limiting for the dephosphorylation of IDH which results when preferred carbon sources are added to cultures growing on acetate. SN - 0300-9084 UR - https://www.unboundmedicine.com/medline/citation/2557093/Isocitrate_dehydrogenase_kinase/phosphatase_ DB - PRIME DP - Unbound Medicine ER -