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Isocitrate dehydrogenase kinase/phosphatase exhibits an intrinsic adenosine triphosphatase activity.
J Biol Chem. 1987 Nov 25; 262(33):16095-9.JB

Abstract

In Escherichia coli, isocitrate dehydrogenase (IDH) is regulated by reversible phosphorylation. The bifunctional enzyme which catalyzes this phosphorylation cycle, IDH kinase/phosphatase, also exhibits a specific ATPase activity. Mutant derivatives of this protein which are nearly devoid of IDH phosphatase activity retain both IDH kinase and ATPase activity, indicating that ATP hydrolysis does not result from the cyclic phosphorylation of IDH. However, the IDH kinase and ATPase activities of these mutant proteins differ significantly from those of the wild-type IDH kinase/phosphatase expressed from the parental allele. This observation suggest that IDH kinase and IDH phosphatase do not reside on structurally independent domains. In contrast to many enzymes which catalyze kinetically unfavorable side reactions, the maximum velocity of the ATPase substantially exceeded those of IDH kinase and IDH phosphatase. ATP hydrolysis was only partially inhibited by phospho- and dephospho-IDH, with saturating levels of phospho-IDH decreasing the rate of ATP hydrolysis by a factor of approximately 5. Even in the presence of near-saturating concentrations of phospho-IDH, the rate of ATP hydrolysis was 4-fold greater than the rate of the cyclic phosphorylation of IDH.

Authors+Show Affiliations

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

Pub Type(s)

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

Language

eng

PubMed ID

2824478

Citation

Stueland, C S., et al. "Isocitrate Dehydrogenase Kinase/phosphatase Exhibits an Intrinsic Adenosine Triphosphatase Activity." The Journal of Biological Chemistry, vol. 262, no. 33, 1987, pp. 16095-9.
Stueland CS, Eck KR, Stieglbauer KT, et al. Isocitrate dehydrogenase kinase/phosphatase exhibits an intrinsic adenosine triphosphatase activity. J Biol Chem. 1987;262(33):16095-9.
Stueland, C. S., Eck, K. R., Stieglbauer, K. T., & LaPorte, D. C. (1987). Isocitrate dehydrogenase kinase/phosphatase exhibits an intrinsic adenosine triphosphatase activity. The Journal of Biological Chemistry, 262(33), 16095-9.
Stueland CS, et al. Isocitrate Dehydrogenase Kinase/phosphatase Exhibits an Intrinsic Adenosine Triphosphatase Activity. J Biol Chem. 1987 Nov 25;262(33):16095-9. PubMed PMID: 2824478.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Isocitrate dehydrogenase kinase/phosphatase exhibits an intrinsic adenosine triphosphatase activity. AU - Stueland,C S, AU - Eck,K R, AU - Stieglbauer,K T, AU - LaPorte,D C, PY - 1987/11/25/pubmed PY - 1987/11/25/medline PY - 1987/11/25/entrez SP - 16095 EP - 9 JF - The Journal of biological chemistry JO - J Biol Chem VL - 262 IS - 33 N2 - In Escherichia coli, isocitrate dehydrogenase (IDH) is regulated by reversible phosphorylation. The bifunctional enzyme which catalyzes this phosphorylation cycle, IDH kinase/phosphatase, also exhibits a specific ATPase activity. Mutant derivatives of this protein which are nearly devoid of IDH phosphatase activity retain both IDH kinase and ATPase activity, indicating that ATP hydrolysis does not result from the cyclic phosphorylation of IDH. However, the IDH kinase and ATPase activities of these mutant proteins differ significantly from those of the wild-type IDH kinase/phosphatase expressed from the parental allele. This observation suggest that IDH kinase and IDH phosphatase do not reside on structurally independent domains. In contrast to many enzymes which catalyze kinetically unfavorable side reactions, the maximum velocity of the ATPase substantially exceeded those of IDH kinase and IDH phosphatase. ATP hydrolysis was only partially inhibited by phospho- and dephospho-IDH, with saturating levels of phospho-IDH decreasing the rate of ATP hydrolysis by a factor of approximately 5. Even in the presence of near-saturating concentrations of phospho-IDH, the rate of ATP hydrolysis was 4-fold greater than the rate of the cyclic phosphorylation of IDH. SN - 0021-9258 UR - https://www.unboundmedicine.com/medline/citation/2824478/Isocitrate_dehydrogenase_kinase/phosphatase_exhibits_an_intrinsic_adenosine_triphosphatase_activity_ DB - PRIME DP - Unbound Medicine ER -