Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ATPase reaction and its pH lability demonstrate three fiber types in the adult mouse gastrocnemius; Type I (light staining with alkaline preincubation and dark with acid preincubation), Type IIA (dark after alkaline preincubation), type IIB (dark after alkaline and acid preincubation). The SDH and NADH-tetrazolium reductase reactions also demonstrate three types of fibers; those low (A), intermediate (B) or high (C) in oxidative enzyme activity. However, the use of both procedures in serial sections demonstrates that four different combinations occur; the IIB fibers are high in SDH activity, the I fibers are intermediate in SDH enzyme activity, while the IIA fibers are either low or intermediate in SDH activity. These fiber types are present within the gastrocnemius muscle in a distinct pattern of zones. The predominant fiber type, located in the superficial half of the muscle, is the IIA (A) fiber which is high in ATPase and low in SDH activity. This is consistent with the fact that the gastrocnemius is generally considered a white, fast muscle. The IIB and I fibers are fewer in number and are located deeper in the muscle.
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PMID:Skeletal muscle fiber types in the adult mouse. 13 38

An electrophilous inhibitor, p-(N,N-di-2-chloroethyl)amino-phenylacetic acid (I), specifically disturbs the mechanism of respiration and phosphorylation coupling in mitochondria. I inhibits respiration and ATPase activity in intact mitochondria and does not affect these processes in mitochondria and submitochondrial particles with partially or completely impaired coupling system. The data obtained show that I inhibits protonophoric function of NADH-ferricianide reductase from submitochondrial particles soluble ATPases from bovine heart and Micrococcus lysodeikticus mitochondria adsorded on octane water interface and has no effect on respective enzymes in water solutions. Cation-transferring enzymes are shown to behave with respect to the inhibitor on lipid water interface like respective enzymes in intact mitochondria, while in water solutions they behave like those in systems with the impaired coupling mechanism. Effect of I on protonophoric function of oligomycin-sensitive ATPase and bacteriorhodopsin plaques isolated from Halobacterium halobium is also studied. It is shown that the precence or the absence of I effect is due to a nature of lipid in the enzymatic complex. I is found also to inhibit specifically the transport of Ca2+ from water to octane in the presence of Ca2+-ATP-ase from rabbit sarcoplasmic reticulum.
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PMID:[Mechanism of action of the specific inhibitor of respiration and phosphorylation in mitochondria--n-(N,N-di-2-chlorethyl)aminophenylacetic acid]. 13 99

It has been found that metyrapone can inhibit both type I and type II mixed-function oxygenase reactions, while cysteamine inhibits only type I activity in this mammalian system. Following pretreatment with phenobarbital and 3-methylcholanthrene the half-maximal inhibiting concentrations for the O-demethylation of paranitranisol are increased for cysteamine and decreased for metyrapone. Both cysteamine and metyrapone give type II binding spectra with oxidized cytochrome P-450. The negative and positive peaks are at 393 and 426 nm respectively for metyrapone, and 410 and 434 nm for cysteamine. Cysteamine showed no binding comparable to that of metyrapone for reduced cytochrome P-450. Metyrapone showed little or no inhibition of the NADH cytochrome-c reductase (EC 1.6.1.1) or NADPH (EC 1.6.2.3) cytochrome-c reductase while cysteamine had a more or less strong inhibiting effect depending on the pretreatment of animals. Neither the binding to P-450 heme nor the inhibition of NADH and NADPH cytochrome-c reductase correlates well with cysteamine inhibition of total activity. It is therefore suggested that cysteamine reacts with an intermediate electron carrier of non-heme iron or glycoprotein character thus inhibiting mixed-function oxygenase activity.
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PMID:A comparative study on the influence of cysteamine and metyrapone on mixed-function oxygenase activities in variously pretreated liver microsomes from rats and mice. 13 29

Young mycelia of the fungus Neurospora crassa contain a soluble NADH-linked sideramine reductase, which may be responsible for liberating iron in vivo from accumulated sideramines during iron-deficient cultivation. The enzymes can be assayed using a soluble supernatant fraction, EDTA, and an atmosphere of pure nitrogen. The enzyme is stable without loss of activity up to 45 degrees C and has an optimum of activity at pH 7.0. Besides coprogen (Km = 100 micrometer, V=2.8 nmol/min per mg protein), some other ferrichrome-type compounds are reduced. However, ferrichrome, ferrirubin coprogen B and ferrioxamine are poor substrates. When the mucelia were grown in a medium containing 10(-5) M ferri iron, the activity of the reductase was found to be only 30% of that found under low iron conditions. The enzyme is inhibited by oxygen, SH-alkylating agents and partly by some detergents. Unlike the reductase of N. crassa, the corresponding enzyme from Aspergillus fumigatus revealed low reduction of coprogen and high reduction of ferrichrome, indicating genusdependent specificities of sideramine reduction enzymes in fungi. The participation of acids of the citric acid cycle as natural iron acceptors during strong iron deficiency is studied and confirmed by iron uptake measurements on isolated mitochondria.
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PMID:Enzymatic release of iron from sideramines in fungi. NADH:sideramine oxidoreductase in Neurospora crassa. 14 35

Single muscle fibres were isolated by microdissection from freeze-dried samples of rabbit psoas and soleus muscles. The individual fibres were typed according to qualitative histochemical reactions for succinate dehydrogenase or NADH-tetrazolium reductase and for alkaline Ca2+-activated myofibrilla myosin ATPase after acid or alkaline preincubation. Methods are described for electrophoretic analysis by means of polyacrylamide disc electrophoresis in the presence of SDS of total myofibrilla proteins in single fibres after pre-extraction of soluble proteins. Fast-twitch white fibres revealed a myosin light chain pattern characteristic of "fast- type" myosin with three light chains of apparent molecular weights of 22,300 (LC1) 18,400 (LC2) and 16,000 (LC3). Fast-twitch red fibres were indistinguishable in this respect from fast-twist white fibres and showed an identical pattern of myosin light chains. Slow-twitch fibres could be characterized by a myosin light chain pattern typical of myosin of slow-twitch muscles with peptides of the apparent molecular weights of 23,500 (LC1Sa), 23,000 (LC1Sb) and 18,500 (LS2S). Slow-twitch fibres isolated from soleus as well as from psoas muscle were indistinguishable with regard to their myosin light chain patterns, thus suggesting that fibres of the same histochemical type correspond in their myosin light chain patterns irrespective of their origin from different muscles.
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PMID:Myosin light chain patterns of individual fast and slow-twitch fibres of rabbit muscles. 14 18

Human erythrocytes from healthy male donors were fractionated with respect to in vivo age by simple centrifugation in order to characterize changes in the functional integrity of the membrane during the life-span of the cell. The three enzymes, Na/K-ATPase, glyceraldehyde-3-phosphate dehydrogenase and NADH-ferricyanide reductase, were found not to change with age, but significant age-dependent decreases were observed in the cases of acetylcholinesterase, phosphoglycerate kinase, purine nucleoside phosphorylase, adenylate kinase, Mg-ATPase and alkaline phosphatase. The possibility that these changes were attributable to mechanisms other than age-related inactivation, such as reticulocyte contamination, differential resealing and crypticity, was investigated. Only the decrease in acetylcholinesterase could be explained wholly in terms of reticulocyte contamination. A decrease in membrane integrity on ageing was observed, which accounted for approximately half the change in alkaline phosphatase and may have contributed to the other enzyme activity changes. This membrane integrity effect masked a real decrease in the highly cryptic NADH-ferricyanide reductase, this decrease being apparent only after total disaggregation of the membrane with nonionic surfactant.
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PMID:Changes in the activities of some membrane-associated enzymes during in vivo ageing of the normal human erythrocyte. 14 40

Premature infants tolerate respiratory loads poorly. This may reflect incomplete development of the ventilatory muscles (VM) causing poor resistance to fatigue. To study the developmental pattern of human VM, 31 postmortem specimens of diaphragm and intercostal muscles were obtained. Individual muscle fibers were classified as type I (slow-twitch, high-oxidative) or type II (fast-twich, low-oxidative) using histochemical staining methods for myofibrillar adenosine triphosphatase (M-ATPase) (pH 10.30) and nicotinamide adenine dinucleotide (NADH) tetrazolium reductase. In the diaphragm, premature infants (less than 37 wk gestation) had only 9.7 +/- 1.3% type I fibers, full-term newborns 25.0 +/- 1.1%, and older subjects (greater than 2 yr of age) 54.9 +/- 1.3%. There was no further increase after 8 mo postpartum. In the intercostal muscles, premature infants had only 19.0 +/- 4.8% type I fibers, full-term newborns 45.7 +/- 1.3%, and older subjects 65.2 +/- 2.6%. There was no further increase after 2 mo postpartum. These findings suggest the ventilatory muscles of newborn infants are more susceptible to fatigue than those of older subjects. This may contribute significantly to respiratory problems in the neonate.
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PMID:Developmental pattern of muscle fiber types in human ventilatory muscles. 14 79

Added free fatty acids inhibit oxidation of glycerol 3-phosphate, succinate and NADH in brown-adipose tissue mitochondria from 10-day-old rats. The most pronounced is the inhibitory effect of glycerol 3-phosphate cytochrome c reductase (GP-cyto. c reductase). Contrary to other reductases, GP-cyto. c reductase activity of freshly isolated mitochondria is already inhibited by the fraction of endogenous free fatty acids. Both added and endogenous free fatty acids inhibition of GP-cyto. c reductase is fully reversible by the removal of free fatty acids by bovine serum albumine treatment. The inhibition of GP-cyto. c reductase is of strictly non-competitive type. The most inhibitory are unsaturated long-chain free fatty acids-oleic and linoleic acid. Results are discussed with regards to the regulatory importance of free fatty acids in brown-adiposetissue during intensive non-shivering thermogenesis.
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PMID:The regulation of glycerol 3-phosphate oxidase of rate brownadipose tissue mitochondria by long-chain free fatty acids. 16 98

Mitochondrial malate dehydrogenase (L-malate : NAD-+ oxido-reductase, EC 1.1.1.37) was inhibited by potassium tetrachloro platinum (II), K-2PtCl-4, in the presence of varying concentrations of NADH, NAD-+ and L-malate and mixtures of NAD-+ and L-malate. It was observed that NADH is an effective protector of the enzyme from inhibition while both NAD-+ and L-malate are poor protectors. Spectral studies have suggested that the protection afforded by the substrates are accomplished by reaction with specific groups on the enzyme rather than by complexation of the substrates with PtCl-4-2-minus. From the above data it has been concluded that the tetrachloroplatinate ion binds only at the active site and that this site which is effectively protected by NADH, and moderately protected by a NAD-+-L-malate complex probably contains one or more sulfur containing amino acid side chains. It is also proposed that when the tetrachloroplatinate complexes with the enzyme there is some effect, possibly a conformational change, which causes the release of NADH at the allosteric site.
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PMID:Protection of the active site of mitochondrial malate dehydrogenase from inhibition by potassium tetrachloroplatinate. 16 79

It has been reported that cells of Candida utilis, grown in continuous culture under iron-limited conditions, develop site 1 phosphorylation, without the appearance of piericidin sensitivity and without changes in the iron-sulfur centers of NADH dehydrogenase, on aeration in the presence of cycloheximide, as well as on increasing the supply of iron during growth. These findings were reinvestigated in the present study. The parameters and properties followed during these transitions were sensitivity of NADH oxidation to piericidin, presence or absence of coupling site 1, EPR signals appearing on reduction with NADH or dithionite, the specific activities of NADH oxidase, NADH-ferricyanide reductase, and NADH-5-hydroxy-1,4-naphthoquinone (juglone) reductase, and the kinetic behavior of NADH dehydrogenase in the ferricyanide assay. Monitoring the rates of oxidation of NADH in submitochondrial particles with artificial oxidants, observing the kinetics of the ferricyanide assay, and measuring the concentration of iron-sulfur centers elicited by EPR permitted ascertaining the type of NADH dehydrogenase present and its relative concentration in different experimental situations. It was found that on gradually increasing the concentration of iron during continuous culture (transition from ironlimited to iron- and substrate-limited growth), as well as on aeration of iron-limited cells, coupling site 1, piericidin sensitivity, NADH-ferricyanide activity, and iron-sulfur centers 1 and 2 increased concurrently, with concomitant decline of NADH-juglone reductase activity. Cycloheximide prevented all these changes. Iron-sulfur centers 3 plus 4 underwent relatively little increase during these transitions. It is concluded that in both of these experimental conditions a replacement of the type of NADH dehydrogenase present in exponential phase cells by that characteristic of stationary phase cells occurs and that the appearance of site 1 phosphorylation, piercidin sensitivity, and iron-sulfur centers 1 plus 2, all associated with the latter enzyme, is a consequence of this replacement. No evidence was found for the development of coupling site 1 without the appearance of piericidin sensir th
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PMID:Piericiden A sensitivity, site 1 phosphorylation, and reduced nicotinamide adenine dinucleotide dehydrogenase during iron-limited growth of Candida utilis. 16 85


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