Disease relevance of maeB

• We determined the DNA sequence and transcriptional start sites of the genes encoding the diphosphopyridine nucleotide-dependent malic enzyme (DME, EC 1.1.1.39) and the triphosphopyridine nucleotide-dependent malic enzyme (TME, EC 1.1.1. 40) of Rhizobium (Sinorhizobium) meliloti [1].
• Studies on regulatory functions of malic enzymes. VI. Purification and molecular properties of NADP-linked malic enzyme from Escherichia coli W [2].
• Structure and properties of malic enzyme from Bacillus stearothermophilus [3].
• Malic Enzyme Cofactor and Domain Requirements for Symbiotic N2 Fixation by Sinorhizobium meliloti [4].
• YtsJ has the major physiological role of the four paralogous malic enzyme isoforms in Bacillus subtilis [5].

High impact information on maeB

• Involvement of single residue tryptophan 548 in the quaternary structural stability of pigeon cytosolic malic enzyme [6].
• A single open reading frame of 1434 base pairs encoding 478 amino acids was concluded to be that for the malic enzyme gene because the amino acid composition of the enzyme and the sequence of 16 amino acids from the amino terminus of the enzyme agreed well with those deduced from this open reading frame [3].
• An NADP-preferring malic enzyme ((S)-malate:NADP oxidoreductase (oxalacetate-decarboxylating) EC 1.1.1.40) with a specific activity of 36.6 units per mg of protein at 60 degrees C and an isoelectric point of 5.1 was purified to homogeneity from the thermoacidophilic archaebacterium Sulfolobus solfataricus, strain MT-4 [7].
• In addition to the NAD(P)-dependent oxidative decarboxylation of L-malate, S. solfataricus malic enzyme was able to catalyze the decarboxylation of oxalacetate [7].
• A number of differences in the kinetic and physical properties of the Escherichia coli nicotinamide adenine dinucleotide phosphate (NADP+) dependent malic enzyme have been found, depending upon whether Mg2+ or Mn2+ served to fulfill the divalent cation requirement [8].

Chemical compound and disease context of maeB

• NADP-linked malic enzyme [EC 1.1.1.40] was highly purified from Escherichia coli W cells [2].
• Amino acid composition of S. solfataricus enzyme was determined and found to be significantly higher in tryptophan content than the malic enzyme from Escherichia coli [7].
• Role of metal cofactors in enzyme regulation. Differences in the regulatory properties of the Escherichia coli nicotinamide adenine dinucleotide specific malic enzyme depending on whether Mg2+ or Mn2+ serves as divalent cation [9].
• When malic enzyme was induced under appropriate culture conditions in a strain of E. coli that was unable to ferment glucose and accumulated pyruvate, fermentative metabolism of glucose was restored [10].
• Production of succinic acid through overexpression of NAD(+)-dependent malic enzyme in an Escherichia coli mutant [10].

Biological context of maeB

• Neither reductive carboxylation of pyruvate, nor decarboxylation of oxaloacetate, could be detected for either malic enzyme [11].
• The amino acid sequences deduced from partial mle genes were aligned with 22 malic enzyme sequences and the corresponding phylogenetic tree was constructed [12].
• NAD(+)-dependent malic enzyme was cloned from the Escherichia coli genome by PCR based on the published partial sequence of the gene [10].
• A full-length 1927-base-pair cDNA of pigeon liver malic enzyme was obtained by utilizing the screening of the cDNA library and polymerase chain reaction techniques [13].
• However, recombinant E. coli NZN111 (F- Apfl::Cam ldhA::Kan) harboring pTrcML, a plasmid containing the E. coli malic enzyme gene, produced a considerable amount of malic acid along with the desired product, succinic acid [14].

Associations of maeB with chemical compounds

• The sedimentation coefficient (S(0)20, W) was 13.8S, and the molecular activity was 44,700 min-1 at 30 degrees C. The amino acid composition of the enzyme was determined, and the results were compared with those of NAD-linked malic enzyme from the same organism and those of pigeon liver NADP-linked malic enzyme [2].
• The measurement of enzyme activities implied a significant change in metabolism, when alternative pathways such as the Entner-Doudoroff pathway (EDP) and the malic enzyme pathway were activated in the gnd mutant grown on glucose [15].
• The NAD(P)(+) specific malic enzyme [EC 1.1.1.39] exhibits positive co-operativity with respect to malate, but Michaelis-Menten type behavior with respect to the co-factors NAD(+) or NADP(+) [11].
• This latter class of revertants apparently synthesized oxalacetate from malate via the sequential actions of the NAD-linked malic enzyme, phosphoenolpyruvate synthetase, and phosphoenolpyruvate carboxylase [16].
• An extreme case is the four putative malic enzyme genes maeA, malS, ytsJ, and mleA. maeA was demonstrated to encode malic enzyme activity, to be inducible by malate, but also to be dispensable for growth on malate [5].

Regulatory relationships of maeB

• It was found that flux through phosphoenol pyruvate carboxylase and malic enzyme were up-regulated in the pykF- mutant as compared with the wild type, and acetate formation was significantly reduced in the mutant [17].

Other interactions of maeB

• The malic enzyme, involved in the production of pyruvate, and pyruvate dehydrogenase, required for the channelling of pyruvate into acetyl-CoA, were also induced in IAA-treated cells [18].
• The results are strikingly similar to previous results reported on the nicotinamide adenine dinucleotide (NAD+) dependent malic enzyme and the NAD+-dependent isocitrate dehydrogenase, supporting the suggestion that metal cofactors function as regulatory entities [8].

Analytical, diagnostic and therapeutic context of maeB

• Crystallization and preliminary x-ray diffraction analysis of malic enzyme from pigeon liver [19].

References