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)

This study on erythrocytes in hemoglobin H (Hb H) disease reveals that unstable Hb H is bound to membranes to a greater extent, especially when it forms methemoglobin or is precipitated as inclusion body. The methemoglobin content of these erythrocytes is elevated in spite of a higher activity of NADH-methemoglobin reductase. The ATPase activity is doubled, and the ATP is presumably used for phosphorylation of membrane proteins, which leads to cross-linking of membrane proteins. This assumption could be supported by the observed decrease in non-electrolyte permeability, by increased binding of hemoglobin to the membrane and by polymerisation of membrane proteins detected by SDS-polyacrylamide gel electrophoresis. By means of electron microscopy, it could also be shown that the inclusion bodies are bound to the inner surface of membrane and cause its protrusion. This linkage might be responsible for the observed inhibition of the lateral movement of intramembrane particles.
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PMID:Erythrocyte alterations in hemoglobin H disease. 627 17

1. Microsomes were isolated from rabbit fast-twitch and slow-twitch muscle and were separated into heavy and light fractions by centrifugation in a linear (0.3-2m) sucrose density gradient. The membrane origin of microsomal vesicles was investigated by studying biochemical markers of the sarcoplasmic-reticulum membranes and of surface and T-tubular membranes, as well as their freeze-fracture properties. 2. Polyacrylamide-gel electrophoresis showed differences in the Ca(2+)-dependent ATPase/calsequestrin ratio between heavy and light fractions, which were apparently consistent with their respective origin from cisternal and longitudinal sarcoplasmic reticulum, as well as unrelated differences, such as peptides specific to slow-muscle microsomes (mol.wts. 76000, 60000, 56000 and 45000). 3. Freeze-fracture electron microscopy of muscle microsomes demonstrated that vesicles truly derived from the sarcoplasmic reticulum, with an average density of 9nm particles on the concave face of about 3000/mum(2) for both fast and slow muscle, were admixed with vesicles with particle densities below 1000/mum(2). 4. As determined in the light fractions, the sarcoplasmic-reticulum vesicles accounted for 84% and 57% of the total number of microsomal vesicles, for fast and slow muscle respectively. These values agreed closely with the percentage values of Ca(2+)-dependent ATPase protein obtained by gel densitometry. 5. The T-tubular origin of vesicles with a smooth concave fracture face in slow-muscle microsomes is supported by their relative high content in total phospholipid and cholesterol, compared with the microsomes of fast muscle, and by other correlative data, such as the presence of (Na(+)+K(+))-dependent ATPase activity and of low amounts of Na(+)-dependent membrane phosphorylation. 6. Among intrinsic sarcoplasmic-reticulum membrane proteins, a proteolipid of mol.wt. 12000 is shown to be identical in the microsomes of both fast and slow muscle and the Ca(2+)-dependent ATPase to be antigenically and catalytically different, though electrophoretically homogeneous. 7. Basal Mg(2+)-activated ATPase activity was found to be high in light microsomes from slow muscle, but its identification with an enzyme different from the Ca(2+)-dependent ATPase is still not conclusive. 8. Enzyme proteins that are suggested to be specific to slow-muscle longitudinal sarcoplasmic reticulum are the flavoprotein NADH:cytochrome b(5) reductase (mol.wt. 32000), cytochrome b(5) (mol.wt. 17000) and the stearoyl-CoA desaturase, though essentially by criteria of plausibility.
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PMID:Biochemical heterogeneity of skeletal-muscle microsomal membranes. Membrane origin, membrane specificity and fibre types. 628 27

Ischemic myocardium was produced by occluding the left circumflex coronary artery in anesthetized dogs. Autolyzed myocardium was produced by incubating transmural samples of canine left ventricle at 37 degrees C. Tissue pH was recorded continuously in each model using a microcombination pH electrode impaled into the midmyocardium. The activities of the five mitochondrial inner membrane enzyme complexes of electron transport and coupled oxidative phosphorylation were assayed as a function of time of ischemia or autolysis. While the activities of complex II (succinate-CoQ reductase) and IV (cytochrome c oxidase) were completely stable, that of complex I (NADH-CoQ reductase) decreased markedly, but largely only after 20 min of ischemia or autolysis. At 20 min and beyond, the decrease in the activity of complex I paralleled closely the decrease in whole mitochondrial oxygen uptake with NAD-linked substrates in both models. The activity of complex III (CoQH2-c reductase) decreased at a more gradual rate during ischemia or autolysis, and its rate of decrease paralleled that of succinate-supported oxygen uptake. The activity of complex V (oligomycin-sensitive ATPase) decreased most rapidly (by 40% in only 5 min of autolysis) but nearly leveled off beyond 20 min in the two models. A strikingly similar pattern of differential enzyme lability was observed in isolated control mitochondria incubated at lowered pH values. The results demonstrate 1) differential enzyme lability within the mitochondrial inner membrane, 2) a connection between severity of acidosis and the degree of enzyme activity loss, and 3) the usefulness of simple tissue autolysis as an analogue of in situ myocardial ischemia.
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PMID:Mitochondrial complexes I, II, III, IV, and V in myocardial ischemia and autolysis. 630 12

In one experiment Swiss mice were maintained on a 16 or 23% fat diet (laboratory chow with added fat, principally corn oil) or on laboratory chow alone (5.5% fat). In another experiment C57BL/1 mice were given a 23% fat diet (as above) or a low-fat diet (67% laboratory chow, 1.9% corn oil, and 31% starch; 5.5% fat). Colon mucosal samples were analyzed for several enzyme activities. In Swiss mice the analyses revealed the following: 1) Ouabain-insensitive ATPase was unaltered in male mice, but it rose significantly in females fed a high-fat diet (this effect was seen when a resuspended high-speed pellet was analyzed but not seen with the initial homogenate); 2) 5'-nucleotidase activity showed a significant stepwise increase with dietary fat; 3) nonspecific esterase activity tended to rise with a high-fat diet (not significant); 4) beta-glucuronidase levels were not altered by diet fat; and 5) ornithine decarboxylase levels were not altered by diet fat. In C57BL/1 mice analyses were done on ouabain-insensitive ATPase, 5'-nucleotidase, nonspecific esterase, and beta-glucuronidase, but no diet effects were seen. Fecal reductase activity was measured with the use of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride hydrate). A high-fat diet did not affect the activity in C57BL/1 mice, but it caused a significant rise in Swiss mice.
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PMID:High-fat diets and fecal level of reductase and colon mucosal level of ornithine decarboxylase, beta-glucuronidase, 5'-nucleotidase, ATPase, and esterase in mice. 632 44

Ca2+-dependent K+ transport and plasma membrane NADH dehydrogenase activities have been studied in several 'high-K+' (human, rabbit and guinea pig) and 'low-K+' (dog, cat and sheep) erythrocytes. All the species except sheep showed Ca2+-dependent K+ transport. NADH-ferricyanide reductase was detected in all the species and showed positive correlation with the flavin contents of the membranes. NADH-cytochrome c reductase was very low or absent in dog, sheep and guinea pig membranes. No correlation was found between NADH dehydrogenase and Ca2+-dependent K+ channel activities in the species studied. Nor were any of the above activities correlated with (Na+ + K+)-ATPase activity.
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PMID:Plasma membrane nadh dehydrogenase and Ca2+-dependent potassium transport in erythrocytes of several animal species. 640 2

The histochemical fibre type composition of the rat superior and medial rectus (SR and MR), superior oblique (SO) and levator palpebrae superioris (LPS) muscles was studied using the myofibrillar ATPase and NADH-tetrazolium reductase (NADH-TR) techniques. In the SR, MR and SO a peripheral zone containing small fibres and a central zone containing both small and large fibres could be identified. Four fibre types were present in the central zone of these muscles and were categorised as Type 1, Type 2a. Type 2a'. and Type 2b. Four fibre types were also identified in the peripheral zone--Type 1, Type 2a, Type 2a' and Type 2c. In the LPS Type 1, Type 2, Type 2a', Type 2b and Type 2c fibres were evenly intermixed without a zonal arrangement. The Type 1, Type 2a, Type 2b and Type 2c fibres correspond to accepted fibres types in the rat limb muscles. The type 2a' and Type 2a" fibres were differentiated from the Type 2a fibres on the basis of size and pattern and intensity of staining with the NADH-TR technique. The Type 2c fibres, which possess both acid-stable and alkali-stable myofibrillar ATPase, are considered to represent intermediate fibres in the process of transformation from Type 2 to Type 1, rather than fibres with a dual innervation as has been suggested in the past. The implications of these histochemical findings are considered in relationship to the physiology of individual motor units and to the function of the extraocular muscles.
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PMID:A histochemical study of fibre types in rat extraocular muscles. 645 Mar 31

The distribution of Type I and Type II fibers, as determined from histochemical estimation of myofibrillar ATPase activity, was studied within and among the locomotory muscles of the forelimb, trunk, and hindlimb of three mongrel dogs. All Type II fibers had high oxidative capacities as estimated from the histochemical assay for reduced nicotinamide adenine dinucleotide tetrazolium reductase, so they were not further divided into subpopulations. Furthermore, Type I and Type II fibers had similar oxidative potentials as indicated by both histochemistry and biochemistry. Type I fiber populations ranged between 14% and 100% in the muscles sampled. The highest percentages of Type I fibers were found in deep muscles of physiological extensor groups in the arm and thigh that serve to resist gravity (antigravity muscles) when the dog is in the quadrupedal standing position. More superficial muscles in these same groups had fewer Type I fibers. The patterns of Type I fiber distribution among muscles in the antigravity groups of the forearm and leg were the opposite of those in the arm and thigh, with the more superficial muscles of the distal limb segments having more Type I fibers than the deeper muscles. In all limb segments, muscle groups that do not serve to resist gravity did not show as much intermuscular variation. Type I fiber populations in these muscles did not exceed 50%. A stratification of fiber types also existed within muscles, both in extensor and flexor groups, with the deeper portions of the muscles having more Type I fibers than the more superficial portions.
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PMID:Distribution of fiber types in locomotory muscles of dogs. 646 Apr 35

Serial 10-micron cryostat cross-sections of the tensor tympani muscle and of the medial gastrocnemius muscle from adult domestic cats were incubated for myofibrillar ATPase, NADH tetrazolium reductase (NADH-TR), succinic dehydrogenase (SDH), malate dehydrogenase (MDH) and menadione-linked alpha-glycerophosphate dehydrogenase (alpha GPDH). The optical density of individual tensor tympani and gastrocnemius muscle fibres after different incubation procedures was measured photometrically. The absorbance values of the tensor tympani fibres were related to the values of the type I, type IIA and type IIB fibres of the gastrocnemius muscle. Only two different types of fibre could be demonstrated in the tensor tympani, one type resembling the type I and another resembling the type IIA of the gastrocnemius muscle. The findings are discussed in relation to other, recent immunohistochemical studies on cat tensor tympani muscle fibres.
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PMID:Histochemical characteristics of the tensor tympani muscle in relation to the medial gastrocnemius muscle of the cat. 649 59

The postnatal development of extrafusal fibers in the slow-twitch soleus muscle of genetically dystrophic C57BL/6J dy2J/dy2J mice and their normal age-matched controls was investigated by histochemical and quantitative methods at selected ages of 4, 8, 12, and 32 weeks. The majority of fibers in the soleus consisted of two kinds, fast-twitch oxidative-glycolytic (FOG) and slow-twitch oxidative (SO), according to reactions for alkaline-stable and acid-stable myosin ATPase and the oxidative enzyme, NADH-tetrazolium reductase. A minor population of fibers, stable for both alkaline- and acid-preincubated ATPase, but variable in staining intensity for NADH-TR, were designated "atypical" fibers. With age, the normal soleus exhibited a gradual increase in the number and proportion of SO fibers and a reciprocal, steady decline in the percentage of FOG fibers. Atypical fibers were numerous at 4 weeks, but were substantially diminished at later ages. Since total extrafusal fiber number remained relatively constant between the periods examined, this change in relative proportions reflects an adaptive transformation of fiber types characteristic of normal postnatal growth. A striking alteration in the number and distribution of fiber types was associated with the dystrophic soleus. At 4 weeks an 18% reduction in total fiber number was already noted. Subsequently, by 32 weeks a further 22% diminution in overall fiber number had occurred. With age, the absolute number and proportion of dystrophic SO fibers were drastically reduced. In contrast, the percentage of dystrophic FOG fibers increased significantly while their absolute numbers between 4 and 32 weeks remained relatively constant. Atypical fibers in the dystrophic solei were found in elevated numbers at all age groups, particularly at 12 weeks. They may, in part, represent attempts at regeneration or an intermediate stage in fiber-type transformation. Microscopically, both of the major fiber types appeared affected, albeit differently, by the dystrophic process. We suggest that a failure or retardation in the normal postnatal conversion of fiber types within the soleus muscle occurs in this murine model for muscular dystrophy.
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PMID:Abnormal distribution of fiber types in the slow-twitch soleus muscle of the C57BL/6J dy2J/dy2J dystrophic mouse during postnatal development. 665 Apr 41

At 110 d of gestation, fetuses were removed from Ossabaw, Yorkshire and crossbred sows and from sows selected for high (obese) or for low (lean) backfat thickness. Ossabaw and obese fetuses were smaller than lean, Yorkshire and crossbred fetuses (595 +/- 32 and 863 +/- 44 g vs 1,030 +/- 77, 1,380 +/- 1,144 +/- 80 g; means +/- SE), respectively. Minimum fiber diameters in the semitendinosus muscle were larger in obese, lean and Ossabaw fetuses than in Yorkshire and crossbred fetuses (12.9 +/- .3, 12.5 +/- .2 and 11.8 +/- .2 micron vs 10.2 +/- .2 and 11.1 +/- .8 micron), respectively. Histochemical analysis for NADH-tetrazoleum reductase (NADH-TR) and esterase activities indicated no fiber type differentiation and no strain differences. Fiber type differentiation was obvious with acid ATPase histochemistry in muscles from all fetuses. The white portion of the semitendinosus from Ossabaw, obese and lean fetuses had many fibers that contained no histochemically detectable lipid (oil red O staining). The unstained fibers (oil red O) were always the most peripherally located fibers in a fasciculi. In some instances, 50% of the fibers in a fasciculi were not stained for lipid. All the fibers in the red portion of muscle from Ossabaw, obese and lean fetuses contained lipid. All the fibers in the red and white portions of muscles from crossbred and Yorkshire fetuses contained lipid. Muscles from young (1 to 2 d old) Ossabaw, Yorkshire and crossbred pigs were also histochemically analyzed. Analysis for NADH-TR, esterase and alkaline phosphatase (capillary staining) activities indicated no fiber type differentiation and no strain differences. As in the fetuses, the white portion of muscle from Ossabaw pigs had many fibers with no lipid (oil red O). Lipid was present in all fibers in the deep portions of muscle from Ossabaws and in all fibers in both portions of muscle from crossbred and Yorkshire pigs. These results indicate that when lipid staining is used as the criterion, fiber type differentiation is evident in muscle from fetuses and young pigs from strains not genetically selected for muscling (Ossabaw, obese and lean strains). Furthermore, fiber type differentiation is not evident in muscle from strains of pigs genetically selected for greater muscling (crossbred and Yorkshires).
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PMID:Semitendinosis muscle development in several strains of fetal and perinatal pigs. 667 93


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