Disease relevance of NADP

• Immunochemical localization of NADP-specific isocitrate dehydrogenase in Escherichia coli [1].
• A competitive protein binding assay has been developed for methotrexate based on the tight binding of this drug to Lactobacillus casei dihydrofolate reductase (= tetrahydrofolate dehydrogenase; 5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase; EC 1.5.1.3) [2].
• Guided by x-ray crystal structures and molecular modeling, site-directed mutagenesis has been used to systematically invert the coenzyme specificity of Thermus thermophilus isopropylmalate dehydrogenase from a 100-fold preference for NAD to a 1000-fold preference for NADP [3].
• We analyzed the sequence of cDNA or genomic DNA from seven unrelated patients with hemolytic anemia due to the inheritance of variants that are reactivated by NADP+ [4].
• For infected membranes, the addition of NADP enhances the magnitude of cholera toxin-dependent ADP ribosylation and renders the magnitude of pertussis toxin-dependent ADP ribosylation equal to that observed in uninfected membranes [5].

High impact information on NADP

• The presence of a human-specific enzyme identified by this method correlated with the presence of a particular human chromosome permitting assignments of the human cytoplasmic forms of NADP-linked IDH, human PGI, and human HGPRT genes to chromosomes 2, 19, and X, respectively [6].
• Directed mutagenesis and molecular modelling have been used to identify a set of amino-acid side chains in glutathione reductase that confer specificity for the coenzyme NADP+ [7].
• The liver or type I isozyme is expressed at high levels in the liver, has a relatively low affinity for steroids (micromolar Km), catalyzes both dehydrogenation and the reverse reductase reaction, and utilizes NADP+ or NADPH as cofactors [8].
• A 1.65 angstrom refined structure of a recombinant human placenta aldose reductase reveals that the enzyme contains a parallel beta 8/alpha 8-barrel motif and establishes a new motif for NADP-binding oxidoreductases [9].
• Binding of the competitive inhibitor 2'-phospho-AMP (AMP, adenosine monophosphate) places the NADP binding site at the carboxyl-terminal edge of the sheet in a manner similar to the nucleotide binding of the dehydrogenase family [10].

Chemical compound and disease context of NADP

• In contrast, the R plasmid R67-specified dihydrofolate reductase (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) isolated from trimethoprim-resistant Escherichia coli utilized alpha-NADPH and alpha-NADH in addition to the "normal" beta-epimers [11].
• The structure of isocitrate dehydrogenase [threo-DS-isocitrate: NADP+ oxidoreductase (decarboxylating), EC 1.1.1.42] from Escherichia coli has been solved and refined at 2.5 A resolution and is topologically different from that of any other dehydrogenase [12].
• Purified mutant protein from an Escherichia coli expression system showed strongly decreased specific activity, increased Km for NADP and for glucose 6-phosphate, and increased heat lability, which indicates that the defective phenotype is due to 2 synergistic molecular dysfunctions: decreased catalytic efficiency and protein instability [13].
• Glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides is irreversibly inactivated by the 2,3'-dialdehyde of NADP+ (oNADP+) in the absence of substrate [14].
• Catalysis by the NADP-dependent non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) from Streptococcus mutans, a member of the aldehyde dehydrogenase (ALDH) family, relies on a local conformational reorganization of the active site [15].

Biological context of NADP

• The activities of the NAD- and the NADP-linked 15-hydroxyprostaglandin dehydrogenases were measured in 16 preeclamptics (mean diastolic pressure, 108 +/- 13 mmHg) and compared with 16 normotensive controls matched for age (20.8 +/- 5.43 vs. 20.6 +/- 5.16) and gestational week of delivery (34.6 +/- 5.40 vs. 35.0 +/- 5.06) [16].
• Studies on the substrate specificity now revealed that ELI3-2 is an aromatic alcohol: NADP(+) oxidoreductase (benzyl alcohol dehydrogenase) [17].
• Under aerobic conditions that are likely to prevail in chloroplasts in vivo, the optimal concentration of ferredoxin for cyclic photophosphorylation was found to be equal to that required for NADP reduction and about one-tenth of that needed for cyclic photophosphorylation under anaerobic conditions [18].
• Localization of prostaglandin D2 binding protein and NADP-linked 15-hydroxyprostaglandin D2 dehydrogenase in the Purkinje cells of miniature pig cerebellum [19].
• Sepiapterin reductase (7,8-dihydrobiopterin: NADP+ oxidoreductase, EC 1.1.1.153) catalyzes the terminal step in the biosynthetic pathway for tetrahydrobiopterin, the cofactor necessary for aromatic amino acid hydroxylation [20].

Anatomical context of NADP

• These characteristics are consistent with the interpretation that the function of the enzyme in human erythrocytes may be to generate oxidizing potential in the form of NADP+ [21].
• The Y' fraction of hepatic cytosol was exclusively responsible for this activity and 3H was transferred selectively to NADP+ [22].
• In mitochondria, TH utilizes protonmotive force to promote direct hydride ion transfer from NADH to NADP, which are bound at the distinct extramembranous domains I and III, respectively [23].
• A full-length cDNA coding for a mutant dihydrofolate reductase (DHFR; 5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3), cloned from a mouse fibroblast cell line grown in high concentrations of methotrexate (MTX), was microinjected into mouse embryos to produce transgenic mice [24].
• Immunohistochemical studies on the cellular localization of NADP-linked 15-hydroxyprostaglandin D2 dehydrogenase were performed with the same cerebellum and revealed the presence of this enzyme also in the Purkinje cells [19].

Associations of NADP with other chemical compounds

• By a comparison of the 14CO2 produced from D-[1-14C]glucose and from D-[6-14C]glucose in the presence and absence of an electron acceptor (methylene blue), it was demonstrated that regeneration of NADP+ from NADPH was a rate-limiting step for the pentose phosphate pathway in the tumors [25].
• Extraction in the presence of sodium hydroxide and cysteine allows estimates of NADPH and total NADP in human red cells without the erroneously high values of NADP+ obtained with earlier methods [26].
• We suggest that NADP-dependent isocitrate dehydrogenase isoenzymes function in an NADP redox shuttle across the peroxisomal membrane to keep intraperoxisomal NADP reduced [27].
• We have determined the crystal structure of mouse sepiapterin reductase by multiple isomorphous replacement at a resolution of 1.25 A in its ternary complex with oxaloacetate and NADP [28].
• Three crystal structures of the catalytic portion of human HMGR in complexes with HMG-CoA, with HMG and CoA, and with HMG, CoA and NADP(+), provide a detailed view of the enzyme active site [29].

Gene context of NADP

• We have solved the structure of human BVR-B in complex with NADP+ at 1.15 A resolution [30].
• Since the intracellular concentrations of G6P and NADP+ are below their KmS for G6PD, these data suggest that high concentrations of pyrimidine 5'-nucleotides depress pentose phosphate shunt activity in pyrimidin 5'-nucleotidase deficiency [31].
• Thiol titration of the two forms of aldose reductase with Ellman's reagent indicated that two thiol groups were lost when the enzyme was dialyzed in the absence of dithiothreitol or NADP [32].
• Mutational analysis of photosystem I polypeptides in Synechocystis sp. PCC 6803. Subunit requirements for reduction of NADP+ mediated by ferredoxin and flavodoxin [33].
• In isolated wild-type membranes, the rate of flavodoxin reduction and flavodoxin-mediated NADP+ reduction were 800 and 480 mumol/mg of chlorophyll/h, respectively [33].

Analytical, diagnostic and therapeutic context of NADP

• Identification of the binding domain for NADP+ of human glucose-6-phosphate dehydrogenase by sequence analysis of mutants [4].
• A productive NADP+ binding mode of ferredoxin-NADP + reductase revealed by protein engineering and crystallographic studies [34].
• The three-dimensional structure of the SeCys498Cys mutant of rat TrxR in complex with NADP(+) has been determined to 3.0-A resolution by x-ray crystallography [35].
• A solid-phase radioimmunoassay for human glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate: NADP+ 1-oxidoreductase; EC 1.1.1.49) was developed that allowed the specific activity of this enzyme protein to be measured in lysates from whole erythrocyte populations, in lysates from erythrocytes of different ages, and in purified samples [36].
• Treatment of cell cultures for 72 hr with 3-methylcholanthrene (1.0 mM) increases the NADP-dependent ALDH activity in H4-II-EC3 and McA-RH7777 cell lines up to 34- and 11-fold, respectively [37].

References