Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have screened the bloodstream form of Trypanosoma brucei for the presence of enzymes that could serve as markers for the microbodies and the highly repressed mitochondrion of this organism. None of seven known microbody enzymes were detected at all, but glycerol-3-phosphate oxidase, ATPase, isocitrate dehydrogenase, acid phosphatase and part of the hyperoxide dismutase and malate dehydrogenase activities were found to be particle-bound after fractionation of homogenates by differential centrifugation. Part of the ATPase activity was sensitive to oligomycin, an inhibitor of oxidative phosphorylation. This oligomycin-sensitive activity can serve as a specific marker for the mitochondria. More than 80% of the NAD+-linked glycerol-3-phosphate dehydrogenase in T. brucei was found to be particulate and latent. The enzyme could be activated by Triton X-100, by the combined action of sonication and salt, but not by salt alone, and partially by freezing and thawing. We conclude that the NAD+-linked glycerol-3-phosphate dehydrogenase is located inside an organelle.
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PMID:Particle-bound enzymes in the bloodstream form of Trypanosoma brucei. 19 9

A mathematical model of the glycolytic system with the cytoplasmic coenzymes NAD+ and NADH as essential variables is proposed. It has been shown that any increase in the steady-state concentration of NADH will reduce the range of activity of the "generalized" ATPase, wherein the level of ATP is stabilized. Such a reduction in the range of ATP stabilization may be caused by an increasing rate of the pyruvate loss into non-glycolytic pathways, in particular, into mitochondria. This effect may be compensated by increasing oxidation of NADH by the dehydrogenases of H+-transferring cytosol-mitochondrial shuttles (malate-aspartate or alpha-glycerophosphate). The properties of the complete model were compared with those of its simplified version, which takes account only of the phosphotransferase reactions of glycolysis. The effects of various factors, which do not alter the level of NADH in the system, may be studied within the scope of the simplified model.
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PMID:[Effect of NAD recirculation on the mechanism of ATP stabilization in cytoplasm. Mathematical models]. 19 86

1. The properties of membrane vesicles from the extreme thermophile Bacillus caldolyticus were investigated. 2. Vesicles prepared by exposure of spheroplasts to ultrasound contained cytochromes a, b and c, and at 50 degrees C they rapidly oxidized NADH and ascorbate in the presence of tetramethyl-p-phenylenediamine. Succinate and l-malate were oxidized more slowly, and dl-lactate, l-alanine and glycerol 1-phosphate were not oxidized. 3. In the absence of proton-conducting uncouplers the oxidation of NADH was accompanied by a net translocation of H(+) into the vesicles. Hydrolysis of ATP by a dicyclohexylcarbodi-imide-sensitive adenosine triphosphatase was accompanied by a similarly directed net translocation of H(+). 4. Uncouplers (carbonyl cyanide p-trifluoromethoxyphenylhydrazone or valinomycin plus NH(4) (+)) prevented net H(+) translocation but stimulated ATP hydrolysis, NADH oxidation and ascorbate oxidation. The last result suggested an energy-conserving site in the respiratory chain between cytochrome c and oxygen. 5. Under anaerobic conditions the reduction of cytochrome b by ascorbate (with tetramethyl-p-phenylenediamine) was stimulated by ATP hydrolysis, indicating an energy-conserving site between cytochrome b and cytochrome c. However, no reduction of NAD(+) supported by oxidation of succinate, malate or ascorbate occurred, neither did it with these substrates in the presence of ATP under anaerobic conditions, suggesting that there was no energy-conserving site between NADH and cytochrome b. 6. Succinate oxidation, in contrast with that of NADH and ascorbate, was strongly inhibited by uncouplers and stimulated by ATP hydrolysis. These effects were not observed when phenazine methosulphate, which transfers electrons from succinate dehydrogenase directly to oxygen, was present. It was concluded that in these vesicles the oxidation of succinate was energy-dependent and that the reoxidation of reduced succinate dehydrogenase was dependent on the outward movement of H(+) by the protonmotive force. 7. In support of the foregoing conclusion it was shown that the reduction of fumarate by NADH was an energy-conserving process. 8. If the activities of vesicles accurately represent those of the intact organism it appears that in B. caldolyticus the reduction of fumarate to succinate at the expense of reducing equivalents from NADH is energetically favoured over succinate oxidation even under aerobic conditions. This may be related to the need for an ample supply of succinate for haem synthesis in order to provide cytochromes for the organism.
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PMID:The oxidative activities of membrane vesicles from Bacillus caldolyticus. Energy-dependence of succinate oxidation. 20 11

The ontogeny of some of the enzymes connected with carbohydrate metabolism in the testis were studied in the White-Rock chicks. In the first place testicular growth in these chicks relate to their overall growth as measured by their body weights. ATPase and NAD+-dependent succinic dehydrogenase activities decreased both with advancing age and increasing testicular weight. However, these enzymes showed maximum activities at 17 and 28 weeks respectively. NAD+-linked isocitric dehydrogenase activity continually increased with increasing testicular weight and age. It is suggested that during spermatogenesis the activities of these enzymes are controlled by different developmental mechanisms.
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PMID:Age-dependent changes in the activities of ATPase and some pyridine nucleotide-linked enzymes in the chick testis. 21 Jul 74

1. The interaction of NAD+, NADH and various nucleotide analogues with pig kidney alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum) EC 3.1.3.1) has been investigated by kinetic means. Some inhibitors act uncompetitively whereas others markedly increase the slopes of double reciprocal plots suggesting they have some affinity for the free enzyme. 2. The compounds seem to bind to alkaline phosphatase through interactions of their bases with a relatively non-specific region of the enzyme, although it is likely that for those nucleotides having some affinity for the free enzyme there is some attraction between the pyrophosphate backbone and the active site. 3. From studies of the effect of NAD+ and NADH on ATPase activity it was concluded that the substrate inhibition that is characteristic of the ATPase activity of alkaline phosphatase originates from binding of ATP to the site assumed to exist for NAD+ and NADH. The potentiation of NAD+-inhibition of ATPase activity by Mg-2+ is probably a result of the depletion of [ATP-4-] the true substrate. The depletion allows NAD+ to complete more effectively for the active site. 4. Binding of NADH is favoured by protonation of an enzymic group with a pK of approx. 9.0 belonging possibly to a tyrosine residue or a zinc hydrate. 5. A large entropy decrease was found to accompany the binding of NAD+ and NADH to alkaline phosphatase. This may be further evidence of an "induced-fit" mechanism previously suspected because of the synergistic inhibitory effects of adenosine and nicotinamide.
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PMID:Nicotinamide-adenine dinucleotide inhibition of pig kidney alkaline phosphatase. 23 67

A morphological and histochemical study has been made of ovarian surface epithelium during the sexual cycle of seasonally breeding birds: crow (Corvus splendens) and common myna (Acridotheres tristis). The surface epithelium is composed of a single layer of compactly arranged columnar and flat cells in the quiescent ovary. It develops numerous villi during the breeding season. The formation of villi has been correlated with the proliferation of cells which are subsequently incorporated into the ovarian stroma where they appear to form follicle and thecal cells around the growing oocytes as evidenced by the close similarities in the morphological and histochemical characteristics of these cell types. As the ovarian activity increases, the surface epithelial cells show increasing amounts of RNA and proteins, which are indicative of their rapid multiplication. No lipids and enzyme activities of acid and alkaline phosphatases, ATPase. DPN- and TPN- diaphorases and delta5-3beta HSDH have been detected in the surface epithelium of both quiescent and active ovaries.
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PMID:Morphological and histochemical observations on the ovarian surface epithelium during the reproductive cycle of crow (Corvus splendens) and myna (Acridotheres tristis). 45 56

Perfused livers from ethanol pretreated rats utilized ethanol and acetaldehyde at higher rates than appropriate controls. This adaptive increase in hepatic ethanol and acetaldehyde uptake was associated with a marked (greater than 60%) increase in hepatic oxygen uptake. Ethanol uptake in both ethanol-treated and control livers was similarly sensitive to inhibition by 4-methylpyrazole, rotenone, and antimycin A. The adaptive increase in ethanol uptake was apparently specifically abolished by ouabain, an inhibitor of the sodium-plus potassium-activated ATPase. The data are consistent with the hypothesis that chronic treatment with ethanol increases ATPase activity. The ADP produced from these initiating events enters the mitochondrial space and stimulates electron transport and oxygen uptake. As a consequence of these events, a greater rate of NADH reoxidation occurs, resulting in a greater rate of production of NAD+ which stimulates ethanol oxidation via alcohol dehydrogenase and acetaldehyde oxidation via aldehyde dehydrogenase(s).
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PMID:Common mechanism for the adaptive increase in hepatic ethanol and acetaldehyde metabolism due to chronic pretreatment with ethanol. 56 3

The present work is a continuation of our studies on mitochondrial functions and enzyme activities after acute exhaustive swimming in liver and myocardium. In rat heart mitochondria the activities of SDH, cytochrome oxidase and ATPase (DNP-stimulated) increase after swimming and remain at that level until the end of the 22-hour rest period studied. The enzyme complexes--rotenone-sensitive NAD. H-cytochrome c-reductase and succinate-cytochrome c-reductase--decrease their activities in both experimental groups. The reduced activity of these two enzymes is determined by changes in this part of the respiratory chain which occur after the incorporation of DCPIP in the oxidation-reduction processes. The marker enzyme of the outer mitochondrial membranes--rotenone-insensitive NAD.H-cytochrome c-reductase--reveals unchanged activity after swimming and a 22-hour period of rest. The different changes in the activities of enzymes with different localization and organization in heart mitochondria are explained by disorganization of the inner membranes after exhaustive swimming, which could induce both activation of some enzymes and inhibition of others. The effect of certain factors during muscle exercise which could cause the established structural and functional changes in the mitochondria is discussed.
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PMID:Effect of single exhaustive swimming on mitochondrial enzyme activities in rat myocardium. 61 30

In the cells of RH, SPEV and HEp-2 lines irradiated with 6.5 mm radiowaves of 1 mW/cm2 flux density the following phenomena were established: activation of succinate dehydrogenase and ATPase; reduction of cytochrome oxidase, NAD- and NADP-diaphorase, acid and alkaline phosphatase activities; repression of 3H-thymidine incorporation in DNA and of 3H-uridine incorporation in RNA; violation of ultrastructure; suppression of cellular proliferation; decrease of mitotic activity; occurrence of pathological forms of mitosis.
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PMID:[Biological oxidation in cells exposed to microwaves in the millimeter range]. 68 31

The structure and histochemistry of the palmar and plantar skin were studied in four adult male marmosets (two Callithrix jacchus and two Callithrix penicillata). In this skin there exist well-developed epidermal ridges, to which are attached one or two ducts of sweat glands. A thick stratum corneum can be seen in the epidermis, while a distinct stratum lucidum cannot be isolated from the other layers. The stratum granulosum is constituted by one or three layers of cells containing keratohyalin granules. Melanin granulations are mainly concentrated in the basal cells of the epidermal ridges. Dendritic melanocytes and amelanotic melanocytes containing alkaline phosphatase are found among the epidermal cells. Glycogen, UDPG-GT and phosphorylases are mainly present in the middle and lower Malpighian cells of the epidermal ridges. Alkaline phosphatase, ATPase, alanyl amino-peptidase and leucine aminopeptidase were absent in the epidermal cells. SDH, cytochrome oxidase, MAO and a certain number of NAD-dependent dehydrogenases (LDH, ADH, MDH, alpha-GPDH, beta-OHBDH and GDH) showed a stronger reactivity in the basal cells and Malpighian layer. The NADP-dependent enzymes (G-6-PDH, 6-PGDH, cis-aconistase and ICDH) were more reactive in the upper Malpighian layer and stratum granulosum. The stratum corneum showed some acid phosphatase and nonspecific esterase reactivity. The collagenous fibers intertwined with a small number of very thin elastic ones and a larger amount of reticular fibers run almost parallel to the epidermal ridges in the papillary body. In the reticular dermis some fibers are disposed transversely to the epidermal ridges. Meissner corpuscles reactive to butyrylcholinesterase, acetylcholinesterase, nonspecific esterase and G-6-PA are disposed at regular intervals and frequently at each side of the epidermal ridges. Pacinian corpuscles were found only in the hypodermis. The eccrine sweat glands contain glycogen, UDPG-GT and phosphorylase in their secretory, ductal and myoepithelial cells. The secretory part shows a uniform reactivity for every dehydrogenase because it contains only one type of cells (clear cells). The intraepidermal segment of the ducts shows a stronger reactivity to nonspecific esterase and NADP-dependent dehydrogenases than the epithelial cells around it.
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PMID:The skin of the palms and soles of the marmosets (Callithrix jacchus and Callithrix penicillata). 82 86


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