Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.1.3 (ATPase)
 65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anacystis nidulans, a freshwater blue-green alga, has been found to lerate sodium chloride (1 percent by weight) and DDT [1,1,1-trichloro-2,2-bis chlorophenyl) ethane] (800 parts per billion) separately, but growth was inhibited in the presence of both compounds. This inhibition was reversed by an increased calcium concentration. It is possible that inhibition of (Na+,K+)-activated adenosine triphosphatase) by DDT causes this species to lose the ability to lerate sodium chloride.
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PMID:DDT: inhibition of sodium chloride tolerance by the blue-green alga Anacystis nidulans. 426 Aug 31

1. The effect of DDT and DDE on the active transport of D-glucose and L-tyrosine was studied in everted sacs of small intestine. 2. DDT and DDE (10(-5) and 10(-4) M) inhibit the active transport of D-glucose and L-tyrosine. 3. These organochlorine compounds also inhibit the (Na+ + K+)-ATPase from the same tissue, to about the same extent. 4. These results suggest that the inhibition of the active transport is due to an action of DDT and DDE on the sodium pump.
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PMID:Inhibition of the active transport of D-glucose and L-tyrosine by DDT and DDE in the rat small intestine. 612 67

Thinning of the egg shell is produced by p-p'-DDT and DDE in several species of birds. A study was made of the effect of DDE administered in vitro and in vivo on the Ca2+ binding and Ca2+-Mg2+-activated ATPase of a homogenate of the egg shell gland of ducks (Anas platyrhynchos var.). The concentration of Ca2+ was 1 X 10(-4) M and that of MgATP 1 X 10(-3) M. In vitro, DDE in concentrations of 2-16 micrograms/ml of incubation medium inhibited the Ca2+-Mg2+-activated ATPase in a concentration-dependent manner, whereas Mg2+-activated ATPase was not affected by these concentrations. The Ca2+ binding by the homogenate was reduced by DDE in the same concentrations. The sodium azide sensitive Ca2+ binding was most sensitive. In vivo, DDE administered in a concentration of 40 mg/kg dry weight of the food for 45 days reduced the egg shell index by 18% in comparison to controls. After 45 days of treatment the DDE concentrations in the egg shell gland mucosa was 1.20 +/- 0.16 micrograms/g of wet weight, while no DDE was detected in the controls. The Ca2+-Mg2+-activated ATPase was reduced by 32%, whereas the Mg2+-ATPase was not changed. The Ca2+ binding by the homogenate was reduced by 29%, the sodium azide sensitive part being most vulnerable, DDE increased the total Ca content of the egg shell gland mucosa by 44%. Since Ca is transported against a concentration gradient between blood plasma, and the lumen of the shell gland, it is suggested that DDE, by inhibiting the Ca2+-Mg2+-activated ATPase, decreased the Ca translocation over the egg shell gland mucosa.
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PMID:Effect of p-p'-DDE administered in vivo and in vitro on Ca2+ binding and Ca2+-Mg2+-ATPase activity in egg shell gland mucose of ducks. 612 33

1. DDT is a weak inhibitor of the ATPase of housefly muscle mitochondria in the absence of Mg2+ but an activator in the presence of Mg2+. 2. By contrast, DDT and several p,p'-substituted alpha-trichlomethylbenzylanilines were strong inhibitors of the ATPase activity in the presence of the uncoupler, dinitrophenol. 3. Maximum inhibition of the DNP-ATPase was achieved when the ATPase complex was dissociated from its endogenous protein inhibitor. 4. The inhibition by DDT was noncompetitive, maximum at acid pH and independent of temperature. The inhibition was counteracted by exogenous phosphatidylcholine and phosphatidylethanolamine. 5. The ATPase was also activated by NH+4 in the presence of valinomycin. This activation was reversed by K+ and strongly inhibited by DDT. 6. The possible mechanisms involved in the inhibition by DDT are discussed.
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PMID:The effect of DDT and related insecticides on the mitochondrial ATPase of houseflies. 613 82

The pesticide p-p'-DDT and its persistent metabolite p-p'-DDE cause thinning of the eggshells in several species of birds. In earlier investigations on ducks this thinning was found to be associated with a reduction of the ATP-dependent Ca2+ binding to a homogenate of the shell gland mucosal cells by DDE. The activity of a Ca2+-Mg2+-activated ATPase in the homogenate was also decreased on administration of DDE in vivo. We have therefore investigated the in vitro effects of some other chlorinated hydrocarbon pesticides of ecotoxicological interest on the ATP-dependent Ca2+ binding and the Ca2+-Mg2+-activated ATPase activity in a homogenate of the eggshell gland mucosa of the hen and determined the molar concentrations that produced 50% inhibition (=IC50). Several of the investigated compounds, namely toxaphene, chlordane, p-p'-DDD, o-p'-DDE, p-p'-DDT, methoxychlor and PCB (Arochlor 1242), had a similar IC50 to inhibit the Ca2+ binding as p-p'-DDE. Lindane, p-p'-DDA and biphenyl had an IC50 3.3-4 times higher and that of 2.4 D was 13.5 times higher than that of p-p'-DDE. When the IC50 of some of the compounds (p-p'-DDE, PCB, toxaphene, Lindane) was determined that decreased the Ca2+-Mg2+-activated ATPase of the homogenate it was found to be only 18 to 29 per cent of that needed to inhibit the Ca2+ binding by the homogenate. It is therefore probable that some other effect than inhibition of this enzyme is also involved in the Ca2+-binding process and affected by the compounds.
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PMID:The inhibitory effect of some chlorinated hydrocarbon pesticides on the ATP-dependent Ca2+ binding of the particulate fraction of the eggshell gland mucosa cells. 613 49

In vitro effects of DDT and its isomers or metabolites were studied on Na+-K+-ATPase and oligomycin-sensitive (OS) Mg++-ATPase activities at 17, 27 and 37 degrees C in rat brain synaptosomes. Dicofol and methoxychlor were found to be more effective inhibitors of Na+-K+-ATPase and OS Mg++-ATPase than DDT, DDD and DDE. Inhibition of OS Mg++-ATPase by the compounds tested (except DDE) was found to be greater at 17 degrees C than at higher temperatures (17 greater than 27 greater than 37 degrees C), suggesting a negative temperature correlation trend Na+-K+-ATPase was less sensitive to these compounds when compared with OS Mg++-ATPase and the inhibition was greater at higher temperatures (37 greater than 27 greater than 17 degrees C), suggesting a positive temperature correlation trend. Other DDT isomers and metabolites showed variable effects on Na+-K+-ATPase and OS Mg++-ATPases. DDD, but not DDE, inhibited both enzyme activities and the inhibition was independent of temperature. No significant differences were observed in the inhibitory potencies of the various DDT, DDD or DDE ring substitutes studied. The present data indicate that DDT, dicofol and methoxychlor were more effective inhibitors of OS Mg++-ATPase than Na+-K+-ATPase and that the inhibition of the former enzyme had a negative temperature dependence, a feature which parallels toxicity results in insects.
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PMID:Effect of temperature on the inhibition of rat brain synaptosomal ATPases by DDT and its structural analogs. 614 41

Evidence on the mode of action of chlorinated hydrocarbon insecticides is reviewed and discussed. DDT and its analogs act mainly at the nerve axon by interfering with Na+ and K+ conductance gating. Various analogs show excitatory, blocking or both kinds of action depending on whether they interfere with Na-inactivation, activation or both. These actions may be functionally related to inhibition of an ecto Ca2+ ATPase, but at this time there is insufficient evidence to draw that conclusion. Bicyclodienes, lindane and mirex and certain of its analogs act at presynaptic terminals to enhance the release of neurotransmitter. Direct evidence to this action by some compounds is available on cholinergic and glutaminergic junctions, but other kinds of junctions may be affected. This action may be functionally related to inhibition of Ca2+-Mg2+ ATPase which is thought to be identical with the Ca2+ ion pump that maintains low internal Ca+ concentrations.
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PMID:Neurotoxic action of chlorinated hydrocarbon insecticides. 618 62

The positions of the double bond and the cis/trans configurations of six mono-unsaturated C18 fatty acids (FA) showed selectivity for inhibition and stimulation of ATPase activities of tissue homogenate fractions. The 13,000 g and 100,000 g sediments (fractions B and C respectively) of tissues homogenates were used as sources of Na+-K+ ATPase and of oligomycin-sensitive (OS) and -insensitive (OIS) Mg2+ ATPase activities. Tissue source included bovine brain and rat brain, kidney, heart and liver. Cis mono-unsaturated C18 FA caused an apparent uncoupling of mitochondrial coupling factor F1 (Mg2+ ATPase). This was indicated by the loss of oligomycin and 1,1,1-trichloro-2,2 bis (p-chlorophenyl) ethane (DDT) sensitivity in the presence of 50 microM FA (12-C18:1). Thus, a precipitous decrease in OS-Mg2+ AtPase activity of mitochondria was accompanied by an equally steep increase in OIS-Mg2+ ATPase activity. This was especially apparent in the heart tissue preparation. The uncoupling action of the FA was not observed with the trans mono-unsaturated C18 FA, Na+-K+ ATPase activity from a bovine brain nerve ending particle (B) fraction was also sensitive to 12-C18:1 FA. However, inhibitory response of Na+-K+ ATPase activity were different for OS-Mg2+ ATPase activity. The latter (OS) was not sensitive to the trans 12-C18:1, while the former (Na+-K+) was sensitive to both cis and trans forms of 12-C18:1 and inhibition appeared to be dependent on the position of the double bond.
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PMID:In vitro response of ATPase activities in tissue subcellular particle preparations to a series of mono-unsaturated C18 fatty acids. 621 Nov 74

Several pollutants like DDT, atrazine, PCP, and others induce changes of cortisol and glucose levels in serum, variations of the amount of liver glycogen and liver function, and exert changes of the activity of gill ATPase and acetylcholinesterase in brain and serum of carps. There is always a biphasic response, an increase of concentration or enzyme activity for a short time, and a decrease or inhibition of the enzymes after a longer exposure to the pollutants. The time scale, the duration of the period of increase and that of decrease, depends on the concentration and the toxicity of the pollutants. The influence of the pollutants in normal fresh water was compared with the effects occurring in carps acclimated to 1.2% salt water. This condition enables one to show that the carps are more sensitive to the pollutants under this condition. All responses are unspecific. Advice for the use of these tests as criteria for water quality are given.
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PMID:Physiological changes in carps induced by pollution. 622 18

Mitochondrial F1 adenosinetriphosphatase (MF1) was allowed to react with 7-chloro-4-nitro-2,1,3-benzoxadiazole (NBD-Cl) until its NBD label to MF1 molar ratio (n) reached approximately 2.6. The labeled enzyme was then separated and subsequently allowed to react with dithiothreitol (DTT) in a controlled way to have its covalent label partially removed. At various stages of removal of its covalent label, the enzyme was separated and assayed for its value of n and the ratio (r) of specific ATPase activity of the DDT-treated enzyme to that of the unlabeled control sample. Most of the experimental values of r turned out to be significantly higher than the theoretical maximum values for models of the enzyme with three equivalent beta subunits, which have been shown to be equal to (1 - n/3)3 for three alternating sites and (1 - n/3)2 for two alternating sites. On the other hand, the observed values of n and r are consistent with a model of the enzyme based on nonequivalent beta subunits, with one active catalytic site and two latent catalytic sites that normally have only regulatory function. Possible complication in the interpretation of data due to a significant amount of nonspecific labeling by NBD-Cl has also been examined and discussed. In addition, the NBD label has been used, after its transfer from the essential Tyr to the essential Lys, as an internal fluorescent probe to monitor protein conformation change at the active site of MF1. Experimental data show that the binding of adenine nucleotide at the latent site(s) can cause conformational change at the active site and presumably in this way regulate the catalytic property of the active site.
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PMID:Chemical evidence for probably nonequivalent beta subunits in F1 adenosinetriphosphatase. 624 79


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