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)

Of three casein phosphatases isolated from the cytosol of human cord blood erythrocytes two were cobalt-dependent, E2 and E3. In the presence of CoCl2, E2 activity was the most prominent. In addition to casein, E2 dephosphorylated phosvitin and p-nitrophenyl phosphate (p-NPP) with pH optima at 6.8-7.2 for proteins and 9.0 for p-NPP. The native enzyme had a molecular weight of 104,000 daltons after AcA-44 Ultrogel filtration. According to SDS/PAGE it consisted of two subunits, 78,000 and 15,000 daltons. The 104,000-dalton form exhibited Michaelis-Menten kinetics and had the greatest affinity for casein between protein substrates tested. Ethanol denaturated the enzyme by 80%. Optimal activation of E2 phosphatase was achieved with 5 mmol/l CoCl2 which did not affect the catalytic properties of the enzyme but did affect the rate of 'E-S' complex formation. Inorganic pyrophosphate was not inhibitory for the 104,000-dalton enzyme. Judging by all these properties the natural substrate for E2 casein phosphatase could be P-pyruvate kinase.
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PMID:Cobalt-dependent protein phosphatases from human cord blood erythrocytes. II. Further characterization of E2 casein phosphatase. 283 85

Intraventricular administration of ACTH1-24 induces excessive grooming in the rat. Ethogram analysis shows that the peptide does not alter grooming behavior seen in a novel box, but that it prolongs the duration of the grooming bout. Extensive structure-activity studies have been performed which suggest that the active site lies in a region (5-13) of the ACTH molecule. Interestingly, the (1-24) sequence is fully active, whereas (1-10) and (11-24) alone or in combination are inactive, pointing to a specific stereoconformation necessary to induce grooming. However, despite the fact that there are ACTH-and/or alpha-MSH-containing peptidergic neurons, no conclusive evidence is available demonstrating stereospecific, saturable binding sites for these peptides in brain. The analysis of the neural substrate underlying ACTH-induced excessive grooming has been performed by means of electrolytic lesions of specific brain regions and by neuropharmacological manipulations. The data suggest that the periaqueductal gray is the primary target for ACTH and that the activity of neostriatum and accumbens, via a nigro-colliculus-periaqueductal gray pathway, modulates the display of excessive grooming. An important feature of the neural substrate is that it displays single-dose tolerance to the peptide during the first hours after the first peptide injection. It is suggested that the tolerance is a feature of an opioid receptor-containing component of the neural substrate. The molecular mechanism of action of ACTH is complex and may involve different transmembrane signal transduction systems. The peptide decreases the degree of phosphorylation of a neuron-specific, synaptic phosphoprotein B-50 by inhibition of protein kinase C. It is concluded that changes in the degree of phosphorylation of B-50 regulate the activity of the lipid kinase phosphatidylinositol 4-phosphate kinase. Therefore, the B-50 protein seems to be part of a negative feedback loop in the receptor-activated hydrolysis of phosphatidylinositol 4,5-bis-phosphate (PIP2). There is increasing evidence that the molecular mechanism by which ACTH brings about the grooming response involves a change in phosphorylation of B-50. Firstly, the structure-activity relationship of ACTH-induced excessive grooming is nearly identical to that obtained for ACTH-induced inhibition of protein kinase C.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Molecular transduction mechanisms in ACTH-induced grooming. 283 22

The intraperitoneal administration of corticotropin (ACTH) in the rate of 1 and 2 units per 100 g of body weight and that of hydrocortisone in the rate of 1 mg and 5 mg per 100 g body weight were studied for their effects on carbohydrate metabolism rate in musculus gastrocnemius as well as on the level of 11-oxycorticosteroids in blood plasma of rats. The glycogen level in muscles was found to rise 3 hours after ACTH and hydrocortisone administration and it correlated with the hydrocortisone level increase in blood plasma (r = 0.714 and 0.863, respectively); the activity of pyruvate kinase decreased. Simultaneously ACTH did not change while hydrocortisone lowered the phosphorylase activity and the content of both fructose-6-phosphate and lactate.
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PMID:[Effect of corticotropin and hydrocortisone on carbohydrate metabolism in skeletal muscles]. 283 20

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

Injection of insulin to fed rats diminished the concentration of fructose 2,6-bisphosphate in white adipose tissue. Incubation of epididymal fat-pads or adipocytes with insulin stimulated lactate release and sugar detritiation and also decreased fructose 2,6-bisphosphate concentration. Such a decrease was, however, not observed in fat-pads from starved or alloxan-diabetic rats. Incubation of adipocytes from fed rats with various concentrations of glucose or fructose led to a dose-dependent rise in fructose 2,6-bisphosphate which correlated with lactate output and detritiation of 3-3H-labelled sugar. In adipocytes from fed rats, palmitate stimulated the detritiation of [3-3H]glucose without affecting lactate production and fructose 2,6-bisphosphate concentration. Incubation of epididymal fat-pads from fed rats in the presence of antimycin stimulated lactate output but decreased fructose 2,6-bisphosphate concentration. Changes in lipolytic rates brought about by noradrenaline, insulin, adenosine and corticotropin in adipocytes from fed rats were not related to changes in fructose 2,6-bisphosphate or to rates of lactate output. In fed rats, the activity of 6-phosphofructo-2-kinase was not changed after treatment of adipocytes with insulin, noradrenaline or adenosine. It is suggested that the decrease in fructose 2,6-bisphosphate concentration observed after insulin treatment can be explained by the increase in sn-glycerol 3-phosphate, an inhibitor of 6-phosphofructo-2-kinase.
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PMID:Regulation of fructose 2,6-bisphosphate concentration in white adipose tissue. 298 73

The separation of 38 hypophyseal or hypothalamic peptides and proteins by reversed-phase HPLC is described. The efficacy of several supports is discussed: large-pore reversed-phase silica supports turned out to be most effective in the separation of neuropeptides and proteins. The use of high sodium phosphate and phosphoric acid in the eluent resulted in high yields and better separation. On the basis of this procedure, beta-lipotropin, beta-endorphin, and adrenocorticotropic hormone were prepared from porcine pituitary glands, and human neurophysins from human pituitary posterior lobes. Moreover, this system is used for the analysis of the perifusate of pituitary posterior lobes, showing the release of micro-heterogeneous neurophysins.
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PMID:Separation of neuropeptides by HPLC: evaluation of different supports, with analytical and preparative applications to human and porcine neurophysins, beta-lipotropin, adrenocorticotropic hormone, and beta-endorphin. 298 60

We examined the effect of angiotensin II, a calcium-mobilizing hormone on polyphosphoinositide metabolism in isolated rat adrenal glomerulosa cells. In cells preloaded with [32P]phosphate or with [3H]inositol, stimulation with angiotensin resulted in an approx. 40% reduction in the radioactivity of triphosphoinositide (PtdIns4,5P2) within 15 s. Only a slight increase in radioactivity was observed in the subsequent 30 min. Changes in labelling of diphosphoinositide (PtdIns4P) showed similar kinetics. Incorporation studies also showed a reduction in the pool size of [32P]PtdIns4P and [32P]PtdIns4,5P2 in response to angiotensin. Production of inositol phosphates in the absence or presence of lithium, a cation-inhibiting myo-inositol-1-phosphatase, was examined in cells preloaded with [3H]inositol. The results indicate that the production rate of inositol tris- and bisphosphate shows a manifold increase in the first seconds of stimulation and remains enhanced for at least several minutes. The present data suggest that the rate of resynthesis of polyphosphoinositides also increases shortly after the activation of PtdIns4,5P2 phosphodiesterase. Corticotropin, a hormone acting via cyclic AMP, neither affected polyphosphoinositide metabolism nor modified the action of angiotensin II.
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PMID:Polyphosphoinositide metabolism in adrenal glomerulosa cells. 298 37

Results of research reported in this paper show that lithium chloride (LiCl) injection causes a marked and prolonged elevation of adrenocorticotropic hormone (ACTH) and corticosterone. Peak elevations occur within 30 min after injection and continue for 60 to 120 min depending upon the molarity of the LiCl solution. CS preexposures do not alter the pituitary-adrenal response to LiCl. Although this response occurs, evidence argues that pituitary-adrenal activity is neither a sufficient nor essential condition for CTA to occur. It is possible that this prolonged ACTH secretion, which would be essential to maintain corticosterone levels elevated for one to two hours, is acting as a component of the unconditioned response associated with LiCl injections. Under certain types of extinction (forced extinction) the P-A system is activated. Thus, when an animal drinks an aversive solution following deprivation, intake of the solution causes a conditioned elevation of plasma corticosterone. Two measures of CTA, behavioral and hormonal, do not always coincide with one another. Preexposure to the CS alters both behavioral and corticosterone indices of CTA. These two systems will show either a coupling (e.g., parallel change) or a dissociation depending on the number of preexposures prior to conditioning. Manipulating the hormones associated with the pituitary-adrenal system also affects the acquisition of CTA and influences extinction. Thus, if one pretests with dexamethasone phosphate (DEX) prior to the administration of LiCl, CTA is attenuated. It would appear that ACTH is involved in the acquisition of CTA since a central block of ACTH also affects the magnitude of the aversion. If ACTH is injected during recovery, animals show a prolonged suppression of drinking. These data appear to be best explained using a memory-retrieval model. The manipulation of hormones and their effects on CTA appear to follow the effects observed endogenously. Thus, ACTH administered to rats during the conditioning phase does not appear to have any effect upon the learning of the aversion. Since LiCl markedly elevates ACTH, as indicated by prolonged elevations of corticosterone, the additional ACTH given exogenously at the time of conditioning does not appear to add to the effects already attributable to endogenous ACTH. Conversely, DEX given during recovery appears to have no effect upon the recovery function. Because endogenous levels of ACTH are already low during the free extinction procedure, DEX treatment does not appear to further reduce ACTH and has no effect upon recovery.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Glucocorticoid and other hormonal substrates of conditioned taste aversion. 299 Feb 81

Biotinylated photoaffinity derivatives of adrenocorticotropin (ACTH) are potentially useful tools for the identification of ACTH receptors. The hormone can be attached covalently to its receptor by photoactivation, and the presence of biotin in the molecule facilitates isolation of the solubilized hormone-receptor complex on columns of immobilized succinoylavidin (Suc-avidin). Six photoprobes of ACTH1-24 have been prepared by reacting ACTH1-24, [25-biocytin]ACTH1-25 amide, and [25-dethiobiocytin]ACTH1-25 amide with either 4- or 5-azido-2-nitrophenylsulfenyl (4-NAPS and 5-NAPS, respectively) chlorides in acetic acid. The homogeneity of the photoprobes was carefully monitored by thin-layer chromatography and amino acid analyses of acid hydrolysates. The presence of underivatized starting material in the photoprobes was critically scrutinized by high-pressure liquid chromatography and was estimated to be less than 0.5%. Both the 4- and 5-NAPS derivatives stimulated maximal steroidogenesis (as compared with ACTH1-24) in calf adrenal cortical cells. However, the potencies of the two isomers differed significantly. The ED50 for steroidogenesis with 5-NAPS-ACTH1-24 was 100-fold greater than the standard (ACTH1-24) while that for 4-NAPS-ACTH1-24 was only approximately 7 times greater. Although 4-NAPS-ACTH1-24 was capable of stimulating maximal adenosine cyclic 3',5'-phosphate (cAMP) production, the 5-NAPS derivative was usually not. The level of stimulation with the 5-NAPS derivative varied considerably from cell preparation to cell preparation. ACTH1-24-induced cAMP production was inhibited by 5-NAPS-ACTH1-24 or 5-NAPS-[25-dethiobiocytin]ACTH1-25 amide.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Synthetic tools for adrenocorticotropin receptor identification. 299 May 45

Rat brain membranes were incubated in N-ethylmaleimide (NEM, 0.5-1.0 mM) in the presence and absence of various concentrations of morphine, Leuenkephalin and human beta-endorphin (beta h-EP). After sufficient washing, the binding of dihydromorphine (DHM), [D-Ala-D-Leu]-enkephalin (DADLE) and tritiated beta h-EP was 10-40% above that of membranes treated with NEM alone. There was no additive effect of morphine and Leu-enkephalin with respect to their effect on recovery of beta h-EP binding. Evaluation of beta h-EP as protecting ligand proved to be difficult since preincubation completely inhibits subsequent DHM and DADLE binding unless a more extensive washing protocol is employed. A protocol for washing beta h-EP preincubated membranes using a Tris-phosphate buffer of pH 6 containing 150 mM NaCl, 20 mM MgCl2 and 10% glycerol was used to recover enough binding potential to evaluate the effects of beta h-EP preincubation towards NEM treatment. Preincubation with beta h-EP itself at 0.1-1.0 microM did not result in any increased recovery of opiate binding, in contrast to the findings with the other two ligands.
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PMID:Beta-endorphin does not protect alkylation of opiate receptor by N-ethylmaleimide. 299 Nov 53


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