Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Na,K-ATPase from duck salt gland and ox brain in the membrane-bound or solubilized form was studied by the radiation inactivation technique using ATP, CTP, GTP or p-NPP as substrates. The values of radiation inactivation size (RIS) were compared with the target size (TS) for the alpha-subunit of the enzyme obtained by an independent method as well as with analytical centrifugation data obtained for C12E8-solubilized enzyme. It was concluded that during ATP (CTP) hydrolysis the enzyme operates as an oligomeric structure; the complex formation requires the presence of K+ and adenosine triphosphate binding to the sites with a low affinity for the nucleotide. Specially designed experiments revealed that the degree of enzyme oligomerization increases with an increase in the microviscosity of the membrane lipid environment.
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PMID:Na,K-ATPase: radiation inactivation studies. 216 88

We studied the testis of Wistar rats weighing 280-300 gms. following the administration of a single, acute intracardiac dose of methionine-enkephalin (100 microliters of 50% met-enkephalin solution), or a chronic intramuscular dose (50 microliters of 40% met-enkephalin solution). Rats were sacrificed at 15, 30 and 60 minutes following acute injection. Those on chronic treatment were injected once daily for 10 or 20 days. For the study, we utilized 105 male Wistar rats; 30 comprised the control group, and 75 comprised the study group. The following staining methods were used: 1) succinate dehydrogenase, 2) lactate dehydrogenase, 3) ATPase, 4) acid phosphatase, 5) alkaline phosphatase. We observed marked histoenzymological changes in the rat testis. Particularly noteworthy was a marked change in the energy pathways consisting of a decreased activity of aerobic pathways (decreased SDH activity), increased anaerobic activity (increased LDH activity), and consequently, decreased cellular energy stores (decreased ATPase activity). Similarly, changes were observed in other nonspecific enzymes that led to a fall in acid phosphatase activity and a rise in alkaline phosphatase activity.
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PMID:[Effects of met-enkephalin on the testis. III. Histoenzymatic study]. 253 59

The radiation inactivation analysis of Na+, K+-ATPase, (EC 3.6.1.37) from two different sources was carried out using ATP, CTP, GTP and p-NPP as substrates. In the case of Na+, K+-ATPase from the bovine brain the relation between the logarithm of the residual activity and the radiation dose is strictly linear, which permits calculating 75-90 kDa (for 3 mM GTP and 10 mM p-NPP). Duck salt glands Na+, K+-ATPase reveals larger target sizes: 350 kDa for ATP hydrolysis in saturating concentrations and 145-190 kDa in the case of GTP and p-NPP or low concentration of ATP (30 microM). A conclusion is drawn that while hydrolyzing substrates with complex kinetics (ATP and CTP) the enzyme functions like oligomer. The interaction of nucleotide with substrate-binding site of low affinity induces the aggregation of monomers.
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PMID:[Study of the interaction of Na+,K+-ATPase protomers using the molecular target method]. 283 45

The character of temperature dependence of hydrolytic and transport functions of Na, K-ATPase is analyzed. It is shown that the nonlinear Arrhenius plot is typical only of "allosteric" substrates ATP and CTP, the inflection of curves reflecting sensitivity of the enzyme to the phase reconstructions of membrane lipids. The linear Arrhenius plots are typical of GTP, UTP- p-NPP and acetyl phosphate, the substrates demonstrating "normal" kinetics of Michaelis and not providing the active transport of ions. A conclusion is drawn that anomalies on the Na, K-ATPase temperature dependence evidence for the lipid control of intersubunit interactions in the supermolecular complex of Na, K-ATPase which are realized during the active transport of ions.
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PMID:[Characteristics of temperature dependence of Na,K-ATPase]. 284 87

Atrial natriuretic factor (ANF) inhibits basal and stimulated aldosterone synthesis in adrenal glomerulosa cells. ANF probably acts through specific membrane receptors. Alterations in cyclic GMP and cyclic AMP levels do not account for ANF's inhibitory effect. ANF does not block angiotensin II (AngII) receptors nor does it interfere with phosphoinositide metabolism or calcium movements stimulated by adrenal agonists. ANF does not inhibit protein synthesis nor does it work by inhibiting NA+,K+-ATPase or depleting cell potassium. ANF decreases conversion of endogenous cholesterol to pregnenolone, the step stimulated by adrenocorticotropin and AngII. ANF does not affect the conversion of 20-alpha-hydroxycholesterol, which easily penetrates mitochondrial membranes to the site of the cholesterol side-chain cleavage enzyme. These results suggest that ANF inhibits the ability of endogenous cholesterol to reach or interact with the side-chain cleavage enzyme. ANF does not act like a calcium channel-blocking agent. However, ANF is less effective at high-calcium concentrations, which suggests that it may inhibit a step that calcium stimulates. Understanding ANF action will probably require identification of the specific biochemical changes (mediators) that it induces. Parallel efforts to understand how other agents stimulate steroidogenesis (particularly in the areas of protein synthesis, protein phosphorylation, and cholesterol movements) will further this understanding.
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PMID:Inhibition of aldosterone synthesis by atrial natriuretic factor. 301 92

The effect of p-nitrophenylphosphate (p-NPP) on the release of acetylcholine evoked by drugs and ionic environments known to inhibit Na+, K+-ATPase was studied in isolated cortical slices of rat brain and longitudinal muscle strip of guinea-pig ileum. p-NPP inhibited the release of acetylcholine induced by sodium deprivation provided that the circumstances were in favour of the function of the K+-activated part of ATPase. However, it failed to antagonize the increase in the acetylcholine release elicited by omission of K+ or by administration of ouabain. Therefore it is concluded that the K+-stimulated phosphatase moiety of the Na+, K+-ATPase might be involved in the release of acetylcholine.
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PMID:Inhibition by p-nitrophenylphosphate of acetylcholine release induced by Na+-deprivation. 303 96

The effect of corticotropin (ACTH1-39), synacthen (ACTH1-24) and hydrocortisone-hemisuccinate on the activity of Ca-ATPase of skeletal muscle sarcoplasmic reticulum (SR) and calcium (Ca) accumulation in SR vesicles has been studied. It has been shown that ACTH1-39 (I U per 100 g body weight) increased the activity of Ca-ATPase in skeletal muscle SR of rats, while hydrocortisone (5 mg per 100 g body weight) did not change the activity of Ca-ATPase in skeletal muscle SR. However, both hormones increase the total activity of ATPase. ACTH1-39 and ACTH1-24 (0.05-0.0005 U/ml) and hydrocortisone (2.8 X 10(-7)-2.8 X 10(-9) mol/l) increased in vitro Ca-ATPase isolated from rabbit skeletal muscle SR and accumulation of Ca is SR vesicles. At the same time, hydrocortisone reduced calcium/phosphorus ratio, while ACTH1-39 and ACTH1-24 increased it, i.e. hydrocortisone facilitated Ca accumulation in SR requiring more ATP energy, whereas ACTH facilitated Ca accumulation in SR requiring less ATP energy.
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PMID:[Effect of corticotropin and hydrocortisone on the Ca2+-ATPase activity of skeletal muscle sarcoplasmic reticulum]. 304 Jan 51

The action of electroacupuncture (EA) may be similar to analgesia by electrode stimulation or transcutaneous nerve stimulation. Since EA may directly stimulate nerve activity or indirectly enhance the release of opiate peptides and other neurotransmitter substances, we have used (Na+ + K+)-ATPase as a model to study the mechanism of action of EA. The membrane-bound (Na + K)-ATPase from purified synaptic plasma membranes inhibited slightly by high concentration of endorphin (30 microM), but not by met-enkephalin up to 6 X 10(-4) M. A single EA treatment for 30 min did not alter the (Na+ + K+)-ATPase activity in the cerebral cortex. However, when rats were treated with low (4 Hz) or high (200 Hz) frequency EA 30 min daily for 3 weeks, both (Na+ + K+)-ATPase and acetylcholinesterase were significantly elevated. The enhanced (Na+ + K+)-ATPase activity after high frequency EA was only partially blocked by i.p. injection of naloxone prior to EA during the last week of the EA treatment program. The results indicated that EA treatment may involve some other neurotransmitter pathways besides opiate peptides.
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PMID:Effect of electroacupuncture on synaptosomal (Na+ + K+)-ATPase. 614 70

Rat bone was extracted with KCl and Triton X-100, and a tartrate-resistant acid phosphatase activity was purified by protamine sulfate precipitation, ion-exchange chromatography (CM-cellulose), and gel filtration on Sephadex G-200 according to previously described procedures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining demonstrated a major band with an apparent monomer molecular size of approximately 14,000 Da. The enzyme is active with p-nitrophenylphosphate (p-NPP) but exhibits a 5- to 10-fold higher affinity towards several nucleotides of which ATP and ADP are the most readily hydrolyzed substrates based on kinetic studies. Based on sensitivity towards proteolytic treatment and detergent removal, as well as pH-optimum studies, a single enzyme was found to be responsible for activity towards nucleotide phosphates as well as p-NPP. This nucleotide tri- and diphosphatase constitutes around 15% of the total acid phosphatase activity in rat bone. The activity with ATP as substrate in contrast to that with p-NPP was inhibited in a noncompetitive fashion by MgCl2, sodium metavanadate, and p-chloromercuribenzoate. Enzyme activity with p-NPP and ATP is dependent on the presence of KCl and detergent and is activated by Fe3+ and ascorbate. The reported characteristics of the enzyme suggest that it functions as a unique membrane acid ATPase.
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PMID:Purification and characterization of a vanadate-sensitive nucleotide tri- and diphosphatase with acid pH optimum from rat bone. 623 50

ATPase activity (E.C. 3.6.1.3.) has been studied by electron microscopy with the help of several cytochemical techniques on Eigenmannia virescens electrocytes. Incubation was carried out with in two different media containing paranitrophenyl phosphate (p-NPP) or adenosine triphosphate (ATP) as substrate. With p-NPP the phosphate freed is captured at alkaline pH, either by strontium chloride or by lead citrate. With ATP the phosphate freed is captured at a pH close to neutrality by the lead nitrate. NaK ATPase activity was only demonstrated with the medium containing ATP; the positive results obtained with this technique were sensitive to ouabain. The enzyme is situated both on the membrane of the posterior face which is innervated and on that of the anterior face of the electrocytes. The cytoplasm of the anterior face is occupied by a strong concentration of tubules on whose membranes the enzyme is also present. The localisation of the enzyme on the tubules can explain biochemical results which indicate that 70% of the total NaK ATPase of the electrolytes is situated at the level of the anterior face.
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PMID:The cytochemical demonstration of NaK dependent adenosine triphosphatase at electrocyte level in Eigenmannia virescens (Gymnotidae). 629 6


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