Interaction of analogues of substrate with NADP-malic enzyme from maize leaves

Spampinato, Claudia P.; Colombo, Sergio; Andreo, Carlos S.

doi:10.1007/bf00027144

Cited by 7 publications

(4 citation statements)

References 21 publications

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“…Previous studies indicate that the decarboxylation reaction shows a pH optimum between 8.0 to 8.4 (Asami et al 1979) and an inhibitory effect of high concentrations of L-malate at pH 7.0 (Spampinato et al 1994). These studies, the velocities for the NADP-ME catalyzed reaction in the decarboxylation and carboxylation directions were assayed at different pH and concentrations of L-malate.…”

Section: Resultsmentioning

confidence: 99%

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Kinetic mechanism of NADP-malic enzyme from maize leaves

Spampinato

Andreo

1995

Photosynth Res

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The kinetic mechanism of NADP-dependent malic enzyme purified from maize leaves was studied in the physiological direction. Product inhibition and substrate analogues studies with 3' aminopyridine dinucleotide phosphate and tartrate indicate that the enzyme reaction follows a sequential ordered Bi-Ter kinetic mechanism. NADP is the leading substrate followed by L-malate and the products are released in the order of CO2, pyruvate and NADPH. The enzyme also catalyzes a slow, magnesium-dependent decarboxylation of oxaloacetate and reduction of pyruvate and oxaloacetate in the presence of NADPH to produce L-lactate and L-malate, respectively.

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Section: Resultsmentioning

confidence: 99%

“…Oxaloacetate is a substrate for the decarboxylation reaction as well as a potent inhibitor of the Lmalate oxidative decarboxylation (Spampinato et al 1994). The ability of malic enzyme to use oxaloacetate as a substrate suggests that this compound is the enzyme-bound intermediate during catalysis.…”

Section: Discussionmentioning

confidence: 99%

Kinetic mechanism of NADP-malic enzyme from maize leaves

Spampinato

Andreo

1995

Photosynth Res

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“…The enzymes responsible for sugar [sucrose-phosphate synthase (SPS), sucrose synthase (SS), hexokinase (HK) and fructokinase (FK)] and acid metabolism [phospho enol pyruvate carboxylase (PEPC), NADP – dependent malic enzyme (NADP-ME) and NAD – malate dehydrogenase (NAD-MDH)] were extracted and measured using the Solarbio enzyme activity kits (Solarbio Life Sciences, Beijing, China) according to the manufacturer’s instructions ( Zhang et al., 2021 ). The extraction kits were based on the earlier determined methods for SPS ( Schrader and Sauter, 2002 ), SS ( Schrader and Sauter, 2002 ), HK ( Pancera et al., 2006 ), FK ( Papagianni and Avramidis, 2011 ), PEPC ( Zhang et al., 2008 ), NADP-ME ( Spampinato et al., 1994 ), and NAD-MDH ( Yao et al., 2011 ).…”

Section: Methodsmentioning

confidence: 99%

Sugar and acid profile of loquat (Eriobotrya japonica Lindl.), enzymes assay and expression profiling of their metabolism-related genes as influenced by exogenously applied boron

et al. 2022

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Soluble sugars and organic acids are the most abundant components in ripe fruits, and they play critical roles in the development of fruit flavor and taste. Some loquat cultivars have high acid content which seriously affect the quality of fruit and reduce the value of commodity. Consequently, studying the physiological mechanism of sugar-acid metabolism in loquat can clarify the mechanism of their formation, accumulation and degradation in the fruit. Minerals application has been reported as a promising way to improve sugar-acid balance of the fruits. In this study, loquat trees were foliar sprayed with 0.1, 0.2 and 0.3% borax, and changes in soluble sugars and organic acids were recorded. The contents of soluble sugars and organic acids were determined using HPLC-RID and UPLC-MS, respectively. The activities of enzymes responsible for the metabolism of sugars and acids were quantified and expressions of related genes were determined using quantitative real-time PCR. The results revealed that 0.2% borax was a promising treatment among other B applications for the increased levels of soluble sugars and decreased acid contents in loquats. Correlation analysis showed that the enzymes i.e., SPS, SS, FK, and HK were may be involved in the regulation of fructose and glucose metabolism in the fruit pulp of loquat. While the activity of NADP-ME showed negative and NAD-MDH showed a positive correlation with malic acid content. Meanwhile, EjSPS1, EjSPS3, EjSS3, EjHK1, EjHK3, EjFK1, EjFK2, EjFK5, and EjFK6 may play an important role in soluble sugars metabolism in fruit pulp of loquat. Similarly, EjPEPC2, EjPEPC3, EjNAD-ME1, EjNAD-MDH1, EjNAD-MDH5-8, EjNAD-MDH10, and EjNAD-MDH13 may have a vital contribution to malic acid biosynthesis in loquat fruits. This study provides new insights for future elucidation of key mechanisms regulating soluble sugars and malic acid biosynthesis in loquats.

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“…The ME enzymatic assay was performed using a method outlined by [ 17 ] with the following modifications. Mosquito mitochondria were homogenized in MSHE containing 2 mM mercaptoethanol.…”

Section: Methodsmentioning

confidence: 99%

Mitochondrial NAD+-dependent malic enzyme from Anopheles stephensi: a possible novel target for malaria mosquito control

Pon

Napoli

Luckhart

et al. 2011

Malar J

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BackgroundAnopheles stephensi mitochondrial malic enzyme (ME) emerged as having a relevant role in the provision of pyruvate for the Krebs' cycle because inhibition of this enzyme results in the complete abrogation of oxygen uptake by mitochondria. Therefore, the identification of ME in mitochondria from immortalized A. stephensi (ASE) cells and the investigation of the stereoselectivity of malate analogues are relevant in understanding the physiological role of ME in cells of this important malaria parasite vector and its potential as a possible novel target for insecticide development.MethodsTo characterize the mitochondrial ME from immortalized ASE cells (Mos. 43; ASE), mass spectrometry analyses of trypsin fragments of ME, genomic sequence analysis and biochemical assays were performed to identify the enzyme and evaluate its activity in terms of cofactor dependency and inhibitor preference.ResultsThe encoding gene sequence and primary sequences of several peptides from mitochondrial ME were found to be highly homologous to the mitochondrial ME from Anopheles gambiae (98%) and 59% homologous to the mitochondrial NADP+-dependent ME isoform from Homo sapiens. Measurements of ME activity in mosquito mitochondria isolated from ASE cells showed that (i) Vmax with NAD+ was 3-fold higher than that with NADP+, (ii) addition of Mg2+ or Mn2+ increased the Vmax by 9- to 21-fold, with Mn2+ 2.3-fold more effective than Mg2+, (iii) succinate and fumarate increased the activity by 2- and 5-fold, respectively, at sub-saturating concentrations of malate, (iv) among the analogs of L-malate tested as inhibitors of the NAD+-dependent ME catalyzed reaction, small (2- to 3-carbons) organic diacids carrying a 2-hydroxyl/keto group behaved as the most potent inhibitors of ME activity (e.g., oxaloacetate, tartronic acid and oxalate).ConclusionsThe biochemical characterization of Anopheles stephensi ME is of critical relevance given its important role in bioenergetics, suggesting that it is a suitable target for insecticide development.

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Interaction of analogues of substrate with NADP-malic enzyme from maize leaves

Cited by 7 publications

References 21 publications

Kinetic mechanism of NADP-malic enzyme from maize leaves

Kinetic mechanism of NADP-malic enzyme from maize leaves

Sugar and acid profile of loquat (Eriobotrya japonica Lindl.), enzymes assay and expression profiling of their metabolism-related genes as influenced by exogenously applied boron

Mitochondrial NAD+-dependent malic enzyme from Anopheles stephensi: a possible novel target for malaria mosquito control

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