Binding and function of mitochondrial glycerol kinase in comparison with those of mitochondrial hexokinase

Kaneko, Munekiyo; Kurokawa, Misuzu; Ishibashi, Shun

doi:10.1016/0003-9861(85)90262-0

Cited by 32 publications

(13 citation statements)

References 15 publications

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“…In spite of the fact that in adult rat brain the rate of oxi dation of 1.0 mM glycerol is about 69% of the rate of oxidation of 1.0 mM glucose (3.17 ver sus 4.62 nmol ,JC 0 2/h/mg protein), glycerol has not generally been considered an impor tant energy substrate for brain [Wieland and Suyter, 1957;Vernon and Walker, 1970;Sokoloff et al, 1977]. However, Kaneko et al [1985] have recently shown that glycerol kinase in brain is linked to glycolysis via the glycerol phosphate shuttle and they have suggested that the role of glycerol kinase in connecting cytosolic metabolism to mito chondrial ATP metabolism is as important as that of hexokinase. Their findings are in agreement with earlier studies which showed that there were substantial levels of glycerol kinase in rat brain and that the enzyme had a sufficiently low Kin (2.0-70 /xM) for glycerol to be a major energy substrate provided suffi cient glycerol were present [Tildon et al, 1976;Jenkins and Hajra, 1976], Taken to gether these studies support the concept that glycerol could be readily utilized as a reserve or alternative fuel for brain energy when in tracellular conditions are unfavorable for the utilization of glucose.…”

Section: Discussionmentioning

confidence: 99%

A Developmental Study of Glycerol Oxidation by Rat Brain

Mc¹,

Mm²,

Jt³

1986

Dev Neurosci

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The rates of oxidation of several concentrations of [1,3–¹⁴C]glycerol to ¹⁴CO₂were measured in whole homogenates of brain from rats of different ages. The rates of oxidation of glycerol at concentrations from 0.1 to 20 mM were significantly lower with brains of neonatal animals than with adult rats, and increased to adult levels during the second to third week of life. The addition of unlabelled glucose decreased the rate of [1,3–¹⁴C]glycerol oxidation by about 40% at all ages and glycerol concentrations. Increasing the initial concentration of glycerol 200-fold from 0.1 to 20 mM resulted in more than a 100-fold increase in the rate of glycerol oxidation. This pattern of an increased rate of oxidation with increasing substrate concentration was in marked contrast to that previously found with other brain energy substrates which levelled off with increasing concentration. The data suggest that glycerol could be an important energy substrate in certain areas or cell types in adult rat brain, or that the ability to oxidize high concentrations of glycerol is a detoxification mechanism to prevent accumulation of excess free glycerol.

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Section: Discussionmentioning

confidence: 99%

A Developmental Study of Glycerol Oxidation by Rat Brain

Mc¹,

Mm²,

Jt³

1986

Dev Neurosci

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“…Thus, functional coupling is the common feature of all studied kinases that can bind to the outer mitochondrial mem brane. However, in rat liver mitochondria, activities of HK and glycerol kinase are negligibly small compared with the activity of omNDPK [16,43].…”

Section: Discussionmentioning

confidence: 88%

10.1007/s10541-008-3013-6

2000

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In the present study, we found that ionic interactions are not essential for the binding of nucleoside diphosphate kinase of liver mitochondria outer compartment to outer mitochondrial membrane and that the proportion of the enzyme activity involved in functional coupling with oxidative phosphorylation (we demonstrated the existence of functional cou pling earlier) is only 17%. Additional evidence was obtained that functionally coupled activity of nucleoside diphosphate kinase is associated with the outer surface of mitochondria. Dextran (10%) did not increase functional coupling. The phys iological importance of these effects is discussed.

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“…Where indicated 20. Phosphorylating respiration rate +CPK -CPK to 0.2 nmol/min per mg protein [38]; nevertheless, mito chondria contain many potential binding sites for these enzymes [21,27,28,38]. Under our experimental condi tions mNDPK catalyzed conversion of ~290 nmol CDP/min per mg protein (assuming that ADP/O = 2, see Table 2).…”

Section: Discussionmentioning

confidence: 98%

Functional Coupling between Nucleoside Diphosphate Kinase of the Outer Mitochondrial Compartment and Oxidative Phosphorylation

Lipskaya

Voinova

2005

Biochemistry (Moscow)

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In rat liver mitochondria all nucleoside diphosphate kinase of the outer compartment is associated with the outer surface of the outer membrane (Lipskaya, T. Yu., and Plakida, K. N. (2003) Biochemistry (Moscow), 68, 1136-1144). In the present study, three systems operating as ADP donors for oxidative phosphorylation have been investigated. The outer membrane bound nucleoside diphosphate kinase was the first system tested. Two others employed yeast hexokinase and yeast nucleoside diphosphate kinase. The two enzymes exhibited the same activity but could not bind to mitochondrial membranes. In all three systems, muscle creatine phosphokinase was the external agent competing with the oxidative phosphorylation system for ADP. Determination of mitochondrial respiration rate in the presence of increasing quantities of creatine phosphokinase revealed that at large excess of creatine phosphokinase activity over other kinase activities (of the three systems tested) and oxidative phosphorylation the creatine phosphokinase reaction reached a quasi-equilibrium state. Under these conditions equilibrium concentrations of all creatine phosphokinase substrates were determined and K(eq)app of this reaction was calculated for the system with yeast hexokinase. In samples containing active mitochondrial nucleoside diphosphate kinase the concentrations of ATP, creatine, and phosphocreatine were determined and the quasi-equilibrium concentration of ADP was calculated using the K(eq)app value. At balance of quasi-equilibrium concentrations of ADP and ATP/ADP ratio the mitochondrial respiration rate in the system containing nucleoside diphosphate kinase was 21% of the respiration rate assayed in the absence of creatine phosphokinase; in the system containing yeast hexokinase this parameter was only 7% of the respiration rate assayed in the absence of creatine phosphokinase. Substitution of mitochondrial nucleoside diphosphate kinase with yeast nucleoside diphosphate kinase abolished this difference. It is concluded that oxidative phosphorylation is accompanied by appearance of functional coupling between mitochondrial nucleoside diphosphate kinase and the oxidative phosphorylation system. Possible mechanisms of this coupling are discussed.

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Binding and function of mitochondrial glycerol kinase in comparison with those of mitochondrial hexokinase

Cited by 32 publications

References 15 publications

A Developmental Study of Glycerol Oxidation by Rat Brain

A Developmental Study of Glycerol Oxidation by Rat Brain

10.1007/s10541-008-3013-6

Functional Coupling between Nucleoside Diphosphate Kinase of the Outer Mitochondrial Compartment and Oxidative Phosphorylation

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