Potent and Competitive Inhibition of Malic Enzymes by Lanthanide Ions

Yang, Zhiru; Batra, Renu; Floyd, Daniel L.; Hung, Hui‐Chih; Chang, Gu‐Gang; Tong, Liang

doi:10.1006/bbrc.2000.3163

Cited by 31 publications

(59 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is similar to reports which found that ATP Citrate Liase (ACL) from Penicillium spiculisporum was also dependent on Mg 2+ for its activity [18] . Mg, Mn and other bivalent ion have also been reported to be important as cofactor for malic enzyme (ME) activity [19,20] .…”

Section: Resultsmentioning

confidence: 99%

Effects of Metal Ion Concentrations on Lipid and Gamma Linolenic Acid Production by Cunninghamella sp. 2A1

Muhid¹,

Nawi²,

Kader³

et al. 2008

OnLine J. of Biological Sciences

View full text Add to dashboard Cite

O on lipid and GLA production by Cunninghamella sp. 2A1 were studied in submerged culture fermentation. Cultivation was performed in 250 ml conical flask (100ml working volume), at 30°C and 250 rpm agitation for 120h. Mg 2+ , Fe 2+ and Zn 2+ have significant effect on lipid accumulation as inclusion of each ions resulted in a 64, 43 and 33% increase in lipid content compared to cultures which was cultivated with the omission of each ions, respectively. All three metal ions also affected GLA production by Cunninghamella sp. 2A1 with Zn 2+ having the most profound effect with an increase of up to 74% of GLA yield (g GLA/g lipidless biomass) achieved. As omission of any single metal ions did not affect biomass concentration achieved, we concluded that metal ions components in production media may have affected lipid and GLA production by affecting pathways involved in the biosynthesis of lipid and GLA. This study reports the critical concentration of each metal ion for optimal lipid and GLA production by Cunninghamella sp. 2A1.

show abstract

Section: Resultsmentioning

confidence: 99%

Effects of Metal Ion Concentrations on Lipid and Gamma Linolenic Acid Production by Cunninghamella sp. 2A1

Muhid¹,

Nawi²,

Kader³

et al. 2008

OnLine J. of Biological Sciences

View full text Add to dashboard Cite

show abstract

“…Both domains B and C adopt an overall ␣/␤/␣ scaffolding. The metal binding site is located at the interface of the two central ␤-sheets of domains B and C. Binding of the metal ion to the enzyme induced rearrangement at the interface regions and thus changed the subunit association affinity (38). The contribution of manganese ion in dual catalytic and stability roles has been proven in several other cases (39 -42) and may be a general case.…”

Section: Discussionmentioning

confidence: 99%

Effect of Metal Binding on the Structural Stability of Pigeon Liver Malic Enzyme

Chang

Chou

Chang

2002

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

The cytosolic malic enzyme from the pigeon liver is sensitive to chemical denaturant urea. When monitored by protein intrinsic fluorescence or circular dichroism spectral changes, an unfolding of the enzyme in urea at 25°C and pH 7.4 revealed a biphasic phenomenon with an intermediate state detected at 4 -5 M urea. The enzyme activity was activated by urea up to 1 M but was completely lost before the intermediate state was detected. This suggests that the active site region of the enzyme was more sensitive to chemical denaturant than other structural scaffolds. In the presence of 4 mM Mn 2؉ , the urea denaturation pattern of malic enzyme changed to monophasic. Mn 2؉ helped the enzyme to resist phase I urea denaturation. The [urea] 0.5 for the enzyme inactivation shifted from 2.2 to 3.8 M. Molecular weight determined by the analytical ultracentrifuge indicated that the tetrameric enzyme was dissociated to dimers in the early stage of phase I denaturation. In the intermediate state at 4 -5 M urea, the enzyme showed polymerization. However, the polymer forms were dissociated to unfolded monomers at a urea concentration greater than 6 M. Mn 2؉ retarded the polymerization of the malic enzyme. Three mutants of the enzyme with a defective metal ligand (E234Q, D235N, E234Q/D235N) were cloned and purified to homogeneity. These mutant malic enzymes showed a biphasic urea denaturation pattern in the absence or presence of Mn 2؉ . These results indicate that the Mn 2؉ has dual roles in the malic enzyme. The metal ion not only plays a catalytic role in stabilization of the reaction intermediate, enol-pyruvate, but also stabilizes the overall tetrameric protein architecture. Pigeon liver malic enzyme ((S)-malate:NADPϩ oxidoreductase (oxaloacetate-decarboxylating), EC 1.1.1.40) is a homotetrameric enzyme with a double dimer quaternary structure. It catalyzes the divalent metal ion-dependent reversible oxidative decarboxylation of L-malate to yield CO 2 and pyruvate with a concomitant reduction of NADP ϩ to NADPH. Cytosolic malic enzyme was first discovered in pigeon liver by Ochoa et al. (1) and was later found to be widespread in nature, from bacteria to human, in both cytosol and mitochondria. In animals and human, the major physiological function of the enzyme is in providing NADPH for the de novo biosynthesis of long chain fatty acids (2, 3). In tumor cells, the mitochondrial malic enzyme is involved in the glutamine metabolism. This provides an energy source for the malignant cells (4 -6).Rutter and Lardy (7) first characterized the requirement of an externally added metal ion in the catalytic mechanism of the malic enzyme. Detailed electron spin resonance and nuclear magnetic resonance studies have delineated the fundamental role of Mn 2ϩ in the malic enzyme-catalyzed reaction (8). With the crystal structure of both mitochondrial and cytosolic malic enzyme having been solved (9 -11), the role of the metal ion in the reaction mechanism of malic enzyme has become clearer. The metal ligands of the enzyme include Asp-258, ...

show abstract

“…Since either Mg 2þ or Mn 2þ were catalytically essential co-factors for normal enzyme activity their replacement led to enzyme deactivation. A strong deactivator of chicken liver malic enzyme was found to be zinc [22], while copper [8] and lanthanide [20] were reported to inhibit both human and pigeon liver malic enzyme. In fact, in pigeon malic enzyme divalent copper ¢rst competitively inhibited enzyme activity, while later oxidative modi¢cation and peptide bond cleavage irreversibly deactivated malic enzyme [10].…”

Section: Discussionmentioning

confidence: 99%

The influence of metal ions on malic enzyme activity and lipid synthesis in Aspergillus niger

Jernejc

2002

FEMS Microbiology Letters

View full text Add to dashboard Cite

In the presence of copper significant induction of citric acid overflow was observed, while concomitantly lower levels of total lipids were detected in the cells. Its effect was more obvious in a medium with magnesium as sole divalent metal ions, while in a medium with magnesium and manganese the addition of copper had a less pronounced effect. Since the malic enzyme was recognised as a supplier of reducing power in the form of reduced nicotinamide adenine dinucleotide phosphate for lipid biosynthesis, its kinetic parameters with regard to different concentrations of metal ions were investigated. Some inhibition was found with Fe 2þ and Zn 2þ , while Cu 2þ ions in a concentration of 0.1 mM completely abolished malic enzyme activity. The same metal ions proportionally reduced the levels of total lipids in Aspergillus niger cells. A strong competitive inhibition of the enzyme by Cu 2þ was observed. It seemed that copper competes with Mg 2þ and Mn 2þ for the same binding site on the protein.

show abstract

Potent and Competitive Inhibition of Malic Enzymes by Lanthanide Ions

Cited by 31 publications

References 27 publications

Effects of Metal Ion Concentrations on Lipid and Gamma Linolenic Acid Production by Cunninghamella sp. 2A1

Effects of Metal Ion Concentrations on Lipid and Gamma Linolenic Acid Production by Cunninghamella sp. 2A1

Effect of Metal Binding on the Structural Stability of Pigeon Liver Malic Enzyme

The influence of metal ions on malic enzyme activity and lipid synthesis in Aspergillus niger

Contact Info

Product

Resources

About