Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

The role of phospholipids in the reduction of ubiquinone analogues by the mitochondrial reduced nicotinamide-adenine dinucleotide-ubiquinone oxidoreductase complex.

ABSTRACT: The isolated NADH-ubiquinone oxidoreductase complex of bovine heart mitochondria reduces ubiquinone analogues by two pathways. One pathway is inhibited by rotenone, and reduction of quinones takes place in the lipid phase of the system. The other pathway is insensitive to rotenone and reduction takes place in the aqueous phase. The variation of rates of electron transpport with the chemical nature of the quinone analogue and the concentrations of both quinone and phospholipid can be rationalized in terms of partition of the quinone between the aqueous and lipid phases of the system. Thus one function of phospholipid associated with the enzyme appears to be to act as solvent for ubiquinone reduced by the rotenone-sensitive pathway. This proposal is supported by the kinetic behaviour of enzyme whose endogenous lipids have been replaced by (1,2)-dimyristoylsn-glycero-3-phosphocholine. Thus, under certain circumstances, the rotenone-sensitive reduction of ubiquinone-1 exhibited a substantial increase in activation energy below the phase-transition temperature of the synthetic lipid, whereas the reduction of other acceptors was unaffected.

SUBMITTER: Ragan CI

PROVIDER: S-EPMC1185729 | biostudies-other | 1978 Jun

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

The interaction of reduced nicotinamide--adenine dinucleotide phosphate with reduced nicotinamide--adenine dinucleotide--ubiquinone reductase from bovine heart mitochondria.

Project description:Reduction of the chromophores of mitochondrial NADH-ubiquinone reductase by NADPH reaches only 50% of the extent of reduction by NADH, monitored at 450 nm. This effect is due to autoxidation of an enzyme component at a higher rate than its reduction by NADPH.

| S-EPMC1163948 | biostudies-other

Nicotinamide adenine dinucleotide as a photocatalyst.

Project description:Nicotinamide adenine dinucleotide (NAD+) is a key redox compound in all living cells responsible for energy transduction, genomic integrity, life-span extension, and neuromodulation. Here, we report a new function of NAD+ as a molecular photocatalyst in addition to the biological roles. Our spectroscopic and electrochemical analyses reveal light absorption and electronic properties of two π-conjugated systems of NAD+. Furthermore, NAD+ exhibits a robust photostability under UV-Vis-NIR irradiation. We demonstrate photocatalytic redox reactions driven by NAD+, such as O2 reduction, H2O oxidation, and the formation of metallic nanoparticles. Beyond the traditional role of NAD+ as a cofactor in redox biocatalysis, NAD+ executes direct photoactivation of oxidoreductases through the reduction of enzyme prosthetic groups. Consequently, the synergetic integration of biocatalysis and photocatalysis using NAD+ enables solar-to-chemical conversion with the highest-ever-recorded turnover frequency and total turnover number of 1263.4 hour-1 and 1692.3, respectively, for light-driven biocatalytic trans-hydrogenation.

| S-EPMC6641943 | biostudies-literature

Specific labelling of a constituent polypeptide of bovine heart mitochondrial reduced nicotinamide-adenine dinucleotide-ubiquinone reductase by the inhibitor diphenyleneiodonium.

Project description:1. NADH-ubiquinone-1 and NADH-menadione reductase activities of Complex I were inhibited by diphenyleneiodonium (apparent Ki 23 and 30 nmol/mg of protein respectively). Reduction of K3Fe(CN)6 and juglone was relatively unaffected. 2. Iodoniumdiphenyl and derivatives were much less effective inhibitors. Compounds with similar ring structures to diphenyleneiodonium, in particular dibenzofuran, were inhibitors of NADH-ubiquinone-1 oxidoreductase. 3. Diphenylene[125I]iodonium specifically labelled a polypeptide of mol.wt. 23500. Maximum incorporation was 1 mol/mol of Complex-I flavin or 1 mol/mol of the 23500-mol.wt. polypeptide. 4. The label associated with this polypeptide was of limited stability, especially at lower pH. 5. Complete inhibition of ubiquinone reduction was achieved when 1 mol of inhibitor was incorporated/mol of Complex-I flavin, but the relationship between inhibition and labelling was not linear. 6. No evidence for covalent interaction between diphenyleneiodonium and the phospholipids of Complex I was obtained. 7. Rotenone increased the apparent affinity of diphenyleneiodonium for the 23500-mol.wt. polypeptide without affecting the maximum incorporation. 8. The 23500-mol.wt. polypeptide was not solubilized by chaotropic agents. Prior treatment of Complex I with chaotropic agents or sodium dodecyl sulphate prevented incorporation of diphenyleneiodonium into this polypeptide.

| S-EPMC1164741 | biostudies-other

Effects of proteolytic digestion by chymotrypsin on the structure and catalytic properties of reduced nicotinamide-adenine dinucleotide-ubiquinone oxidoreductase from bovine heart mitochondria.

Project description:1. Incubation of NADH-ubiquinone oxidoreductase (Complex I) with chymotrypsin caused loss of rotenone-sensitive ubiquinone-1 reduction and an increase in rotenone-insensitive ubiquinone reduction. 2. Within the same time-course, NADH-K(3)Fe(CN)(6) oxidoreductase activity was unaffected. 3. Mixing of chymotrypsin-treated Complex I with Complex III did not give rise to NADH-cytochrome c oxidoreductase activity. 4. Gel electrophoresis in the presence of sodium dodecyl sulphate revealed selective degradation of several constituent polypeptides by chymotrypsin. 5. With higher chymotrypsin concentrations and longer incubation times, a decrease in NADH-K(3)Fe(CN)(6) oxidoreductase was observed. The kinetics of this decrease correlated with solubilization of the low-molecular-weight type-II NADH dehydrogenase (subunit mol.wts. 53000 and 27000) and with degradation of a polypeptide of mol.wt. 30000. 6. Phospholipid-depleted Complex I was more rapidly degraded by chymotrypsin. Specifically, a subunit of mol.wt. 75000, resistant to chymotrypsin in untreated Complex I, was degraded in phospholipid-depleted Complex I. In addition, the 30000-mol.wt. polypeptide was also more rapidly digested, correlating with an increased rate of transformation to type II NADH dehydrogenase.

| S-EPMC1164901 | biostudies-other

Metabolism and biochemical properties of nicotinamide adenine dinucleotide (NAD) analogs, nicotinamide guanine dinucleotide (NGD) and nicotinamide hypoxanthine dinucleotide (NHD).

Project description:Nicotinamide adenine dinucleotide (NAD) is an important coenzyme that regulates various metabolic pathways, including glycolysis, β-oxidation, and oxidative phosphorylation. Additionally, NAD serves as a substrate for poly(ADP-ribose) polymerase (PARP), sirtuin, and NAD glycohydrolase, and it regulates DNA repair, gene expression, energy metabolism, and stress responses. Many studies have demonstrated that NAD metabolism is deeply involved in aging and aging-related diseases. Previously, we demonstrated that nicotinamide guanine dinucleotide (NGD) and nicotinamide hypoxanthine dinucleotide (NHD), which are analogs of NAD, are significantly increased in Nmnat3-overexpressing mice. However, there is insufficient knowledge about NGD and NHD in vivo. In the present study, we aimed to investigate the metabolism and biochemical properties of these NAD analogs. We demonstrated that endogenous NGD and NHD were found in various murine tissues, and their synthesis and degradation partially rely on Nmnat3 and CD38. We have also shown that NGD and NHD serve as coenzymes for alcohol dehydrogenase (ADH) in vitro, although their affinity is much lower than that of NAD. On the other hand, NGD and NHD cannot be used as substrates for SIRT1, SIRT3, and PARP1. These results reveal the basic metabolism of NGD and NHD and also highlight their biological function as coenzymes.

| S-EPMC6739475 | biostudies-literature

Nicotinamide adenine dinucleotide biosynthesis promotes liver regeneration.

Project description:The regenerative capacity of the liver is essential for recovery from surgical resection or injuries induced by trauma or toxins. During liver regeneration, the concentration of nicotinamide adenine dinucleotide (NAD) falls, at least in part due to metabolic competition for precursors. To test whether NAD availability restricts the rate of liver regeneration, we supplied nicotinamide riboside (NR), an NAD precursor, in the drinking water of mice subjected to partial hepatectomy. NR increased DNA synthesis, mitotic index, and mass restoration in the regenerating livers. Intriguingly, NR also ameliorated the steatosis that normally accompanies liver regeneration. To distinguish the role of hepatocyte NAD levels from any systemic effects of NR, we generated mice overexpressing nicotinamide phosphoribosyltransferase, a rate-limiting enzyme for NAD synthesis, specifically in the liver. Nicotinamide phosphoribosyltransferase overexpressing mice were mildly hyperglycemic at baseline and, similar to mice treated with NR, exhibited enhanced liver regeneration and reduced steatosis following partial hepatectomy. Conversely, mice lacking nicotinamide phosphoribosyltransferase in hepatocytes exhibited impaired regenerative capacity that was completely rescued by administering NR.ConclusionNAD availability is limiting during liver regeneration, and supplementation with precursors such as NR may be therapeutic in settings of acute liver injury. (Hepatology 2017;65:616-630).

| S-EPMC5258848 | biostudies-literature

Nicotinamide adenine dinucleotide reduced (NADH) is a natural UV filter of certain bird lens

Project description:In this work, we for the first time report the identification of UV filters in the bird eye lens. We found that lenses of some raptors (black kite, common buzzard) and waterfowl (birds from Podicipedidae family) contain unusually high levels of reduced nicotinamide adenine dinucleotide (NADH)—a compound with high absorption in the UV-A range with a maximum at 340 nm. The lens metabolome of these birds also features an extremely low [NAD +]/[NADH] ratio. Chemometric analysis demonstrates that the differences between the metabolomic compositions of lenses with low and high NADH abundances should be attributed to the taxonomic features of bird species rather to the influence of the low [NAD +]/[NADH] ratio. We attributed this observation to the low metabolic activity in lens fiber cells, which make up the bulk of the lens tissue. Photochemical measurements show that properties of NADH as a UV filter are as good as that of UV filters in the human lens, including strong absorption in the UV-A spectral region, high photostability under both aerobic and anaerobic conditions, low yields of triplet state, fluorescence, and radicals under irradiation. Lenticular UV filters protect the retina and the lens from photo-induced damages and improve the visual acuity by reducing chromatic aberrations; therefore, the results obtained contribute to our understanding of the extremely high acuity of the raptor vision.

| S-EPMC9546832 | biostudies-literature

Mitochondrial nicotinamide adenine dinucleotide reduced (NADH) oxidation links the tricarboxylic acid (TCA) cycle with methionine metabolism and nuclear DNA methylation.

Project description:Mitochondrial function affects many aspects of cellular physiology, and, most recently, its role in epigenetics has been reported. Mechanistically, how mitochondrial function alters DNA methylation patterns in the nucleus remains ill defined. Using a cell culture model of induced mitochondrial DNA (mtDNA) depletion, in this study we show that progressive mitochondrial dysfunction leads to an early transcriptional and metabolic program centered on the metabolism of various amino acids, including those involved in the methionine cycle. We find that this program also increases DNA methylation, which occurs primarily in the genes that are differentially expressed. Maintenance of mitochondrial nicotinamide adenine dinucleotide reduced (NADH) oxidation in the context of mtDNA loss rescues methionine salvage and polyamine synthesis and prevents changes in DNA methylation and gene expression but does not affect serine/folate metabolism or transsulfuration. This work provides a novel mechanistic link between mitochondrial function and epigenetic regulation of gene expression that involves polyamine and methionine metabolism responding to changes in the tricarboxylic acid (TCA) cycle. Given the implications of these findings, future studies across different physiological contexts and in vivo are warranted.

| S-EPMC5927466 | biostudies-literature

Induced transcription-dependent synthesis of mitochondrial reduced nicotinamide-adenine dinucleotide dehydrogenase in Drosophila.

Project description:Salivary glands of Drosophila hydei recovering from an anaerobic treatment show a significant increase in apparent Vmax of mitochondrial NADH dehydrogenase. This increase in Vmax is based on an increase in enzyme molecules resulting from synthesis de novo in the cytoplasm, as indicated by the inhibition by cycloheximide of both the increase in apparent Vmax and the increase in amino acid incorporation into enzyme fractions. The increase in enzyme activity is also inhibited by actinomycin D, which is in support of previous data indicating a casual relationship between transcription in puff 4-81B in the polytene chromosomes and an increase in apparent Vmax of the enzyme. Gel electrophoresis of mitochondrial protein extracts revealed three protein fractions with NADH dehydrogenase activity. All three fractions showed increased activity as well as increased amino acid labelling in glands recovering from anaerobiosis compared with control glands. The data suggest that the increase in mitochondrial NADH dehydrogenase activity in salivary glands recovering from an anaerobic treatment depends on increased gene transcription.

| S-EPMC1172434 | biostudies-other

Nicotinamide adenine dinucleotide is transported into mammalian mitochondria.

Project description:Mitochondrial NAD levels influence fuel selection, circadian rhythms, and cell survival under stress. It has alternately been argued that NAD in mammalian mitochondria arises from import of cytosolic nicotinamide (NAM), nicotinamide mononucleotide (NMN), or NAD itself. We provide evidence that murine and human mitochondria take up intact NAD. Isolated mitochondria preparations cannot make NAD from NAM, and while NAD is synthesized from NMN, it does not localize to the mitochondrial matrix or effectively support oxidative phosphorylation. Treating cells with nicotinamide riboside that is isotopically labeled on the nicotinamide and ribose moieties results in the appearance of doubly labeled NAD within mitochondria. Analogous experiments with doubly labeled nicotinic acid riboside (labeling cytosolic NAD without labeling NMN) demonstrate that NAD(H) is the imported species. Our results challenge the long-held view that the mitochondrial inner membrane is impermeable to pyridine nucleotides and suggest the existence of an unrecognized mammalian NAD (or NADH) transporter.

| S-EPMC6013257 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data