Crystal Structure of the Malic Enzyme fromAscaris suumComplexed with Nicotinamide Adenine Dinucleotide at 2.3 Å Resolution†,‡

Biochemistry ◽  
2002 ◽  
Vol 41 (22) ◽  
pp. 6928-6938 ◽  
Author(s):  
David E. Coleman ◽  
G. S. Jagannatha Rao ◽  
E. J. Goldsmith ◽  
Paul F. Cook ◽  
Ben G. Harris
Keyword(s):  
Crystal Structure ◽  
Nicotinamide Adenine Dinucleotide ◽  
Malic Enzyme ◽  
Nicotinamide Adenine

scholarly journals Effects of glucose on the cytosolic ration of reduced/oxidized nicotinamide-adenine dinucleotide phosphate in rat islets of Langerhans

1979 ◽  
Vol 184 (3) ◽  
pp. 697-700 ◽  
Author(s):  
S J H Ashcroft ◽  
M R Christie
Keyword(s):  
Islets Of Langerhans ◽  
Nicotinamide Adenine Dinucleotide ◽  
Malic Enzyme ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nicotinamide Adenine ◽  
Rat Islets ◽  
Equilibrium Reaction ◽  
Rat Islets Of Langerhans

The maximal extractable activity of “malic” enzyme (EC 1.1.1.40) in rat islets of Langerhans was similar to that reported for liver. Thus “malic” enzyme may catalyse a near-equilibrium reaction in the cytosol of islets of Langerhans. Measurements of islet content of malate and pyruvate, the metabolite substrate and product of “malic” enzyme, were therefore used to calculate the cytosolic ration of [NADPH]/[NADP+]. This ratio was higher in islets incubated with 20 mM-glucose than in islets incubated with 2 mM-glucose.

scholarly journals Interactions of nicotinamide-adenine dinucleotide phosphate analogues and fragments with pigeon liver malic enzyme. Synergistic effect between the nicotinamide and adenine moieties

1987 ◽  
Vol 245 (2) ◽  
pp. 407-414 ◽  
Author(s):  
H J Lee ◽  
G G Chang
Keyword(s):  
Synergistic Effect ◽  
Nicotinamide Adenine Dinucleotide ◽  
Malic Enzyme ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nucleotide Binding ◽  
Phosphate Group ◽  
Nicotinamide Adenine ◽  
Oxidative Decarboxylation ◽  
Wide Range ◽  
Pigeon Liver

The structural requirements of the NADP+ molecule as a coenzyme in the oxidative decarboxylation reaction catalysed by pigeon liver malic enzyme were studied by kinetic and fluorimetric analyses with various NADP+ analogues and fragments. The substrate L-malate had little effect on the nucleotide binding. Etheno-NADP+, 3-acetylpyridine-adenine dinucleotide phosphate, and nicotinamide-hypoxanthine dinucleotide phosphate act as alternative coenzymes for the enzyme. Their kinetic parameters were similar to that of NADP+. Thionicotinamide-adenine dinucleotide phosphate, 3-aminopyridine-adenine dinucleotide phosphate, 5′-adenylyl imidodiphosphate, nicotinamide-adenine dinucleotide 3′-phosphate and NAD+ act as inhibitors for the enzyme. The first two were competitive with respect to NADP+ and non-competitive with respect to L-malate; the other inhibitors were non-competitive with NADP+. All NADP+ fragments were inhibitory to the enzyme, with a wide range of affinity, depending on the presence or absence of a 2′-phosphate group. Compounds with this group bind to the enzyme 2-3 orders of magnitude more tightly than those without this group. Only compounds with this group were competitive inhibitors with respect to NADP+. We conclude that the 2′-phosphate group is crucial for the nucleotide binding of this enzyme, whereas the carboxyamide carbonyl group of the nicotinamide moiety is important for the coenzyme activity. There is a strong synergistic effect between the binding of the nicotinamide and adenosine moieties of the nucleotide molecule.

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