The role of 6-phosphogluconate dehydrogenase in Rhizobium

1977 ◽  
Vol 23 (9) ◽  
pp. 1293-1298 ◽  
Author(s):  
Kalemani Mulongoy ◽  
Gerald H. Elkan
Keyword(s):  
Enzyme Activity ◽  
Nicotinamide Adenine Dinucleotide ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Pentose Phosphate ◽  
Nicotinamide Adenine ◽  
Phosphogluconate Dehydrogenase ◽  
Ketonic Group ◽  
Fast Growing Rhizobia

A nicotinamide adenine dinucleotide (NAD) linked 6-phosphogluconate (6-PG) dehydrogenase has been detected in Rhizobium. The enzyme activity is similar in both slow- and fast-growing rhizobia. The nicotinamide adenine dinucleotide phosphate (NADP) dependent 6-PG dehydrogenase was detected only in the fast growers and was more than twice as active as the NAD-linked enzyme. Partial characterization of the products of 6-PG oxidation in Rhizobium suggests that the NADP-linked enzyme is the decarboxylating enzyme of the pentose phosphate (PP) pathway (EC 1.1.1.44) whereas a phosphorylated six-carbon compound, containing ketonic group(s), is the product of the oxidation catalyzed by the NAD-linked enzyme.

scholarly journals Cellular and mitochondrial mechanisms of atrial fibrillation

2020 ◽  
Vol 115 (6) ◽  
Author(s):  
Fleur E. Mason ◽  
Julius Ryan D. Pronto ◽  
Khaled Alhussini ◽  
Christoph Maack ◽  
Niels Voigt
Keyword(s):  
Atrial Fibrillation ◽  
Nicotinamide Adenine Dinucleotide ◽  
Molecular Mechanisms ◽  
Treatment Options ◽  
Specific Treatment ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Nicotinamide Adenine ◽  
Mitochondrial Activity ◽  
Atp Production

AbstractThe molecular mechanisms underlying atrial fibrillation (AF), the most common form of arrhythmia, are poorly understood and therefore target-specific treatment options remain an unmet clinical need. Excitation–contraction coupling in cardiac myocytes requires high amounts of adenosine triphosphate (ATP), which is replenished by oxidative phosphorylation in mitochondria. Calcium (Ca2+) is a key regulator of mitochondrial function by stimulating the Krebs cycle, which produces nicotinamide adenine dinucleotide for ATP production at the electron transport chain and nicotinamide adenine dinucleotide phosphate for the elimination of reactive oxygen species (ROS). While it is now well established that mitochondrial dysfunction plays an important role in the pathophysiology of heart failure, this has been less investigated in atrial myocytes in AF. Considering the high prevalence of AF, investigating the role of mitochondria in this disease may guide the path towards new therapeutic targets. In this review, we discuss the importance of mitochondrial Ca2+ handling in regulating ATP production and mitochondrial ROS emission and how alterations, particularly in these aspects of mitochondrial activity, may play a role in AF. In addition to describing research advances, we highlight areas in which further studies are required to elucidate the role of mitochondria in AF.

NAD(P)H oxidase–dependent platelet superoxide anion release increases platelet recruitment

Blood ◽  
2002 ◽  
Vol 100 (3) ◽  
pp. 917-924 ◽  
Author(s):  
Florian Krötz ◽  
Hae Young Sohn ◽  
Torsten Gloe ◽  
Stefan Zahler ◽  
Tobias Riexinger ◽  
...  
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Thrombus Formation ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Human Platelets ◽  
Nicotinamide Adenine ◽  
Irreversible Aggregation ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Specific Peptide

Abstract Platelets, although not phagocytotic, have been suggested to release O2−. Since O2−-producing reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) oxidases can be specifically activated by certain agonists and are found in several nonphagocytotic tissues, we investigated whether such an enzyme is the source of platelet-derived O2−. We further studied which agonists cause platelet O2−release and whether platelet-derived O2− influences thrombus formation in vitro. Collagen, but not adenosine 5′-diphosphate (ADP) or thrombin, increased O2− formation in washed human platelets. This was a reduced nicotinamide adenine dinucleotide (NADH)–dependent process, as shown in platelet lysates. Consistent with a role of a platelet, NAD(P)H oxidase expression of its subunits p47phox and p67phoxand inhibition of platelet O2− formation by diphenylene-iodoniumchloride (DPI) and by the specific peptide-antagonist gp91ds-tat were observed. Whereas platelet-derived O2− did not influence initial aggregation, platelet recruitment to a preformed thrombus following collagen stimulation was significantly attenuated by superoxide dismutase (SOD) or DPI. It was also inhibited when ADP released during aggregation was cleaved by the ectonucleotidase apyrase. ADP in supernatants of collagen-activated platelets was decreased in the presence of SOD, resulting in lower ADP concentrations available for recruitment of further platelets. Exogenous O2−increased ADP- concentrations in supernatants of collagen-stimulated platelets and induced irreversible aggregation when platelets were stimulated with otherwise subthreshold concentrations of ADP. These results strongly suggest that collagen activation induces NAD(P)H oxidase–dependent O2− release in platelets, which in turn enhances availability of released ADP, resulting in increased platelet recruitment.

scholarly journals LOCALIZATION OF NICOTINAMIDE ADENINE DINUCLEOTIDE PHOSPHATE-DEPENDENT DEHYDROGENASES IN CATECHOLAMINE-CONTAINING NEURONS OF RAT BRAIN STUDIES ON THE NUCLEUS LOCUS CERULEUS

1974 ◽  
Vol 22 (1) ◽  
pp. 20-28 ◽  
Author(s):  
F. C. KAUFFMAN ◽  
F. E. BLOOM ◽  
K. L. SIMS ◽  
V. M. PICKEL
Keyword(s):  
Brain Stem ◽  
Rat Brain ◽  
Nicotinamide Adenine Dinucleotide ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Locus Ceruleus ◽  
Nicotinamide Adenine ◽  
High Concentration ◽  
Intense Staining ◽  
Phosphogluconate Dehydrogenase ◽  
Glucose 6 Phosphate Dehydrogenase

Histochemical and cytochemical methods have been used to localize glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, isocitrate (nicotinamide adenine dinucleotide phosphate (NADP)) dehydrogenase and malic enzyme in the nucleus locus ceruleus and other catecholamine-containing neuronal groups of the rat brain stem. The four NADP-dependent dehydrogenases were studied by both quantitative and qualitative histochemical techniques using adjacent tissue sections. Both types of analyses were done on neuronal nuclei known to contain catecholamines in high concentration, the nucleus locus ceruleus and the superior cervical sympathetic ganglion; other known catecholamine-containing nuclei were surveyed by the cytologic technique only. There was intense staining of cell bodies and neuropil of the nucleus locus ceruleus after all four of the NADP dehydrogenase histochemical reactions. In contrast, little staining was observed in the adjacent vestibular nuclei or mesencephalic root nucleus of the trigeminal with the exception of appreciable glucose 6-phosphate dehydrogenase activity present in neuropil elements. Quantitative microchemical determinations in the nucleus locus ceruleus corroborate the histochemical results which indicated high NADP dehydrogenase activities particularly for 6-phosphogluconate dehydrogenase. This same pattern of high NADP enzyme activity as determined by combined cytochemical and quantitative chemical techniques was also observed in the superior cervical ganglion and cytochemically in other catecholamine-containing nuclei of the brain stem. Our findings suggest that a high capacity to generate or utilize nicotinamide adenine dinucleotide phosphate (reduced) may be characteristic of those neurons which either receive adrenergic terminals or synthesize catecholamines.

Sign in / Sign up

Export Citation Format

Share Document