Selective Modification of Mitochondrial Malate Dehydrogenase Activity by Changes in Ionic Strength

Kun, Ernest; Eanes, Robert Z.; Volfin, Pierre

doi:10.1038/2141328a0

Cited by 29 publications

(10 citation statements)

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“…malate þ NAD þ ), as previously described. 36) The isolated IMS and matrix fractions were dialyzed with 50 mM K þ -phosphate buffer pH 7.4 for 60 min at 4 C. Fifty mL (10-50 mg protein) of the samples was added to 950 mL of reaction mixture containing 50 mM K þ -phosphate buffer, pH 7.4, 0.2 mM NADH, and 0.4 mM oxaloacetate. Activity was determined by measuring the decrease in NADH absorbance at 340 nm in a spectrophotometer at 25 C for 0-4 min.…”

Section: Methodsmentioning

confidence: 99%

Cisplatin Binding and Inactivation of Mitochondrial Glutamate Oxaloacetate Transaminase in Cisplatin-Induced Rat Nephrotoxicity

Ozaki

Ishiguro

Itoh

et al. 2013

Bioscience, Biotechnology, and Biochemistry

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Section: Methodsmentioning

confidence: 99%

Cisplatin Binding and Inactivation of Mitochondrial Glutamate Oxaloacetate Transaminase in Cisplatin-Induced Rat Nephrotoxicity

Ozaki

Ishiguro

Itoh

et al. 2013

Bioscience, Biotechnology, and Biochemistry

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“…A nonmonotonic response of mMDH to phosphate ions has been demonstrated for the reverse reaction (Kun et al 1967). Mg 2c has been reported to have an activating effect on the forward reaction in blood serum (Wong and Smith 1976;Smith 1983).…”

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confidence: 99%

Enzymatic pattern processing

Zauner

Conrad

2000

Naturwissenschaften

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“…It differs from the cytoplasmic malate dehydrogenase in showing substrate inhibition by oxalacetate at neutral pH. As in the case of glutamate dehydrogenase, this inhibition is sensitive to solution variables [7], The pig-heart enzyme has a molecular weight of 70000 and is composed of two similar subunits. The mitochondrial enzyme is much less stable in neutral solution than is the supernatant enzyme.…”

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confidence: 99%

The Interaction of Glutamate Dehydrogenase and Malate Dehydrogenase with Phospholipid Membranes

Dodd

1973

European Journal of Biochemistry

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The interaction between sonicated dispersions of purified phospholipids, corresponding to those found in the inner mitochondrial membrane, and the enzymes was studied by kinetic and spectroscopic methods.With glutamate dehydrogenase the charge type of the lipid head group determines the extent of lipid-protein complexing. Phosphatidylcholine did not significantly alter the activity of the enzyme a t lipid concentrations up to 1 mM, and the nuclear magnetic resonance (NMR) spectrum of the lipid (lolo, w/v) was not altered in the presence of enzyme (up to 2O/,, w/v).Phosphatidylethanolamine did not affect the activity in the oxidation of glutamate, but interfered with the assay in the reverse direction, possibly owing to Schiff-base formation with 2-oxoglutarate. The negatively charged cardiolipin, which is found uniquely in the inner mitochondrial membrane, strongly and reversibly inhibited the enzyme (50 O/,, inhibition with 0.1 -20 pM lipid, depending on conditions). Another anionic phospholipid, phosphatidylserine (which does not occur in mitochondria), also inhibited the enzyme, but less effectively (50°/, inhibition a t about 8 pM). The lipid-enzyme interaction decreases with increasing ionic strength, indicating an electrostatic contribution to the binding. NMR studies suggest that there is also an apolar interaction involving the lipid chains.The studies with malate dehydrogenase concentrated on detecting possible stabilization of this enzyme through interaction with lipids. A clear-cut stabilization was found with lysophosphatidylcholine. Under conditions such that the enzyme alone lost 50°/, on the initial activity in about 2 h, lysophosphatidylcholine gave a slight (2O0lO) activation and this activity remained constant for several hours. NMR studies indicated that, as with the related enzyme 3-hydroxybutyrate dehydrogenase, both the polar choline head group and the hydrocarbon chains are involved in the binding of the lipid to the protein.These specific lipid * protein complexes are probably examples of allotopic interactions. This form of complexing may explain aspects of the behaviour of these enzymes in vivo.The allosteric interactions of enzyme systems have been extensively studied both experimentally and theoretically and these interactions are now &mly established as a major regulatory mechanism for cellular metabolism [i]. Another possible major regulatory mechanism may utilize allotopic interactions but this effect has not been extensively studied [2]. This paper reports our attempts to identify and study allotopic interactions of some mitochondrial NAD-linked dehydrogenases. The previous uncertainty about the localization of dehydrogenases within the mitochondrion has been clarified by recent work [3]. The inner membrane-matrix fraction of mitochondria retains most of the integrated functions which are characteristic of whole mitochondria. 3-Hydroxybutyrate dehydrogenase is bound very tightly to the inner mitochondrial membrane, whilst glutamate dehydrogenase and malate dehydrogenase are found ...

show abstract

Selective Modification of Mitochondrial Malate Dehydrogenase Activity by Changes in Ionic Strength

Cited by 29 publications

References 7 publications

Cisplatin Binding and Inactivation of Mitochondrial Glutamate Oxaloacetate Transaminase in Cisplatin-Induced Rat Nephrotoxicity

Cisplatin Binding and Inactivation of Mitochondrial Glutamate Oxaloacetate Transaminase in Cisplatin-Induced Rat Nephrotoxicity

Enzymatic pattern processing

The Interaction of Glutamate Dehydrogenase and Malate Dehydrogenase with Phospholipid Membranes

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