Wyniki wyszukiwania

1

Basic properties of the pyruvate dehydrogenase complex isolated from aurochs heart

100%

Czygier M., Strumilo S. A.

Acta Biochimica Polonica

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1994

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tom 41

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nr 4

The purified aurochs (Bison bonasus, European bison) heart pyruvate dehydrogenase complex (PDC) has a set of subunits typical of mammalian PDC. PDC from aurochs heart contains firmly bound tiamine pyrophosphate in the amount providing over 50% of the maximal activity of the complex. The apparent value for activation energy of PDC is 60 kJ/mol. The Michael is constant values for aurochs heart PDC are 22.4 ± 1.0,3.3 ± 0.1 and 24.4 ± 3.6 uM for pyruvate, CoA and NAD, accordingly. Acetyl-CoA is a competitive inhibitor with respect to CoA (Ki = 14.2 ± 0.4 uM), whereas NADH gives the same inhibition with respcct to NAD (Ki = 46.9 +10.0 uM). The Km for CoA and NAD of the aurochs heart PDC are lower than that of domestic animals PDC.

2

Short-term regulation of the mammalian pyruvate dehydrogenase complex

75%

Strumilo S.

Acta Biochimica Polonica

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2005

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tom 52

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nr 4

In this minireview the main mechanism of control of mammalian pyruvate dehydrogenase complex (PDHC) activity by phosphorylation-dephosphorylation is presented in the first place. The information recently obtained in several laboratories includes new data about isoforms of the PDH converting enzymes (kinase and phosphatase) and their action in view of short-term regulation of PDHC. Moreover, interesting influence of exogenous thiamine diphosphate (TDP) and some divalent cations, especially Mn2+, on the kinetic parameters of PDHC saturated with endogenous tightly bound TDP, is discussed. This influence causes a shortening of the lag-phase of the catalyzed reaction and a strong decrease of the Km value of PDHC mainly for pyruvate. There are weighty arguments that the effects have an allosteric nature. Thus, besides reversible phosphorylation, also direct manifold increase of mammalian PDHC affinity for the substrate by cofactors seems an important aspect of its regulation.

3

Pyruvate dehydrogenase kinase - a molecular enigma

63%

Miernyk J. A., Thelen J. J., Randall D. D.

Cellular and Molecular Biology Letters

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1998

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tom 03

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nr 3

4

The dependence of electrophoretic and spectroscopic properties of the pyruvate dehydrogenase complex on mono- and divalent ions

63%

Pawelczyk T., Easom R. A., Olson M. S.

Acta Biochimica Polonica

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1994

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tom 41

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nr 1

The effects of various mono- and divalent ions on the pyruvate dehydrogenase complex (PDC) were investigated. To determine the radius of PDC under various conditions a two-dimensional agarose gel electrophoresis technique was used. The radius of PDC cross-linked with glutaraldehyde at ionic strength 0.04 M was calculated to be 22.0 ± 0.1 nm. The presence of K+, Na+ or HPO4 prevented changes in electromobility and of the calculated radius of PDC induced by alteration in ionic strength. The fluorescence emission spectra of PDC depended on the ionic strength and monovalent cations. The fluorescence intensity of PDC increased in the presence of 80 mM K+, and decreased in the presence of 80 mM Na+ with no shift in the emission maximum wavelength. Changes in the ionic strength to which PDC was exposed resulted in alteration of the UV absorption spectra in the 230 nm region. These alterations were prevented by HPO42- , whereas N+ or K+ ions had no effect on the UV absorption spectrum of PDC.

Ograniczanie wyników

3 Acta Biochimica Polonica

1 Cellular and Molecular Biology Letters

1 Czygier M.

1 Easom R. A.

1 Miernyk J. A.

1 Olson M. S.

1 Pawelczyk T.

1 Randall D. D.

1 Strumilo S.

1 Strumilo S. A.

1 Thelen J. J.

1 2005

1 1998

2 1994

Basic properties of the pyruvate dehydrogenase complex isolated from aurochs heart

Short-term regulation of the mammalian pyruvate dehydrogenase complex

Pyruvate dehydrogenase kinase - a molecular enigma

The dependence of electrophoretic and spectroscopic properties of the pyruvate dehydrogenase complex on mono- and divalent ions