Maize recombinant non-C4 NADP-malic enzyme: a novel dimeric malic enzyme with high specific activity

Plant Mol Biol. 2004 May;55(1):97-107. doi: 10.1007/s11103-004-0472-z.


Among the different isoforms of NADP-malic enzyme (NADP-ME) involved in a wide range of metabolic pathways in plants, the NADP-ME that participates in C(4)-photosynthesis is the most studied. In the present work, the expression in E. coli of a cDNA encoding for a maize non-photosynthetic NADP-ME is presented. The recombinant NADP-ME thus obtained presents kinetic and structural properties different from the enzyme previously purified from etiolated leaves and roots. Moreover, the recombinant non-photosynthetic NADP-ME presents very high intrinsic NADP-ME activity, which is unexpected for a non-C( 4) NADP-ME. Using antibodies against this recombinant enzyme, an immunoreactive band of 66 kDa is detected in different maize tissues indicating that the 66 kDa-NADP-ME is in fact a protein expressed in vivo. The recombinant NADP-ME assembles as a dimer, although the results obtained indicate that a higher molecular mass oligomeric state of the enzyme is found in maize roots in vivo. In this way, maize presents at least three NADP-ME isoforms: a 72 kDa constitutive form (previously characterized); the novel non-photosynthetic 66 kDa isoform characterized in this work (which is the product of the ZmChlMe2 gene and the likely precursor to the evolution of the photosynthetic C(4) NADP-ME) and the 62 kDa isoform (implicated in C(4) photosynthesis). The contribution of the present work anticipates further studies concerning the equilibrium between the oligomeric states of the NADP-ME isoforms and the evolution towards the C(4) isoenzyme in maize.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Blotting, Western
  • Cloning, Molecular
  • DNA, Complementary / chemistry
  • DNA, Complementary / genetics
  • Dimerization
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Plant
  • Isoenzymes / chemistry
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Kinetics
  • Malate Dehydrogenase / chemistry
  • Malate Dehydrogenase / genetics*
  • Malate Dehydrogenase / metabolism
  • Molecular Sequence Data
  • Molecular Weight
  • Recombinant Proteins / genetics
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Zea mays / enzymology
  • Zea mays / genetics*


  • DNA, Complementary
  • Isoenzymes
  • Recombinant Proteins
  • Malate Dehydrogenase
  • malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+)

Associated data

  • GENBANK/AY315822