NADP‐malic enzyme from plants: a ubiquitous enzyme involved in different metabolic pathways

Abstract

NADP-malic enzyme (NADP-ME) is a widely distributed enzyme that catalyzes the oxidative decarboxylation of L-malate. Photosynthetic NADP-MEs are found in C4 bundle sheath chloroplasts and in the cytosol of CAM plants, while non-photosynthetic NADP-MEs are either plastidic or cytosolic in various plants. We propose a classification of plant NADP-MEs based on their physiological function and localization and we describe recent advances in the characterization of each isoform. Based on the alignment of amino acid sequences of plant NADP-MEs, we identify putative binding sites for the substrates and analyze the phylogenetic origin of each isoform, revealing several features of the molecular evolution of this ubiquitous enzyme.

Identification of Domains Involved in Tetramerization and Malate Inhibition of Maize C4-NADP-Malic Enzyme

“…2 Members of the Researcher Career of the Consejo Nacional de Investigaciones Científicas y Té cnicas. 3 To whom correspondence should be addressed. Tel.…”

“…In plants, both plastidic and cytosolic NADP-ME (EC 1.1.1.40) playing photosynthetic as well as non-photosynthetic roles have been identified (3). The photosynthetic plastidic isoform, which is expressed in bundle sheath cells of some C 4 plants, represents a unique and specialized form of NADP-ME with particular kinetic, structural, and regulatory properties, and all of these make this enzyme suitable to participate in the CO 2 concentrating mechanism that increases the photosynthetic yield of NADP-ME C 4 plants (3,4).…”

“…The photosynthetic plastidic isoform, which is expressed in bundle sheath cells of some C 4 plants, represents a unique and specialized form of NADP-ME with particular kinetic, structural, and regulatory properties, and all of these make this enzyme suitable to participate in the CO 2 concentrating mechanism that increases the photosynthetic yield of NADP-ME C 4 plants (3,4). In contrast, C 4 nonphotosynthetic NADP-ME isoforms are expressed in the cytosol (5) and plastids (6 -9).…”

Malic enzyme: the controlling activity for lipid production? Overexpression of malic enzyme in Mucor circinelloides leads to a 2.5-fold increase in lipid accumulation

“…In plants, there is a wide range of functions for ME, which is regarded as a ubiquitous enzyme that is involved in a variety of different metabolic pathways, ranging from a role in photosynthesis to other still unknown roles (Drincovich et al, 2001). Thus, identifying the correct ME gene involved in generating NADPH specifically for fatty acid biosynthesis may not be an easy task.…”

Alteration of the Interconversion of Pyruvate and Malate in the Plastid or Cytosol of Ripening Tomato Fruit Invokes Diverse Consequences on Sugar But Similar Effects on Cellular Organic Acid, Metabolism, and Transitory Starch Accumulation

“…This has led to the suggestion that PEPCK is involved in this dissimilation and that part of this dissimilated malate may be used in gluconeogenesis (Leegood and Walker, 2003;Famiani et al, 2005Famiani et al, , 2009. In contrast, NADP-ME isoforms function in chloroplasts and the cytosol (Drincovich et al, 2001;Gerrard Wheeler et al, 2005) and catalyze the reversible conversion of malate and pyruvate (Farineau, 1977;Drincovich et al, 2001). In tomato, NADP-ME has been implicated in respiration during ripening, providing pyruvate and/or NADPH as a substrate for respiration (Farineau, 1977;Edwards and Andreo, 1992).…”