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Thermodynamic studies of binary and ternary complexes of pig heart lactate dehydrogenase

Title data

Schmid, Franz X. ; Hinz, Hans J. ; Jaenicke, Rainer:
Thermodynamic studies of binary and ternary complexes of pig heart lactate dehydrogenase.
In: Biochemistry. Vol. 15 (13 July 1976) Issue 14 . - pp. 3052-3059.
ISSN 0006-2960
DOI: https://doi.org/10.1021/bi00659a018

Abstract in another language

The thermodynamics of the reaction catalyzed by pig heart muscle lactate dehydrogenase (LDH; EC1.1.1,27) have been studied in 0,2 M potassium phosphate buffer, pH 7, over the temperature range of 10 to 35 degrees C by using oxamate and oxalate to simulate the corresponding reactions of the substrates pyruvate and lactate, respectively. The various complexes formed are characterized by Gibbs free energies, enthalpies, and entropies. The Gibbs free energies were determined by equilibrium dialysis investigations, fluorescence titrations, and ultraviolet difference spectroscopy, while the reaction enthalpies stem from direct calorimetric measurements, Formulas are given for both the temperature dependence of the equilibrium constants and the variation with temperature of the enthalpies involved in the four reactions between LDH and NADH or NAD, LDH-NADH and oxamate, and LDH-NAD and oxalate. All reactions show a marked negative temperature coefficient, deltacp, of the binding enthalpies indicating partial refolding to be associated with binary and ternary complex formation. This interpretation appears very probable in view of recent x-ray crystallographic studies on lactate dehydrogenase from dogfish, which demonstrate a volume decrease to occur on binding of oxamate to the LDH-NADH complex. The validity of the thermodynamic parameters, as derived with substrate analogues, for the actual catalytic reaction, gains strong support from the agreement between the sum of the heats involved in the four intermediary reactions reported in this study and direct determinations of the overall enthalpy associated with the catalytic process published in the literature.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: PubMed-ID: 182202
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors > Professorship Biochemistry - Univ.-Prof. Dr. Franz Xaver Schmid
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Professorship Biochemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors
Result of work at the UBT: No
DDC Subjects: 500 Science > 540 Chemistry
Date Deposited: 12 May 2015 06:22
Last Modified: 12 May 2015 06:22
URI: https://eref.uni-bayreuth.de/id/eprint/13286