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)

In Pseudomonas aeruginosa, the effect of different cations on the acid phosphatase activity was studied in order to acquire more information related to a previously proposed mechanism, involving the coordinated action of this enzyme with phospholipase C. Although the natural substrate of this enzyme is phosphorylcholine, in order to avoid the possible interaction of its positive charge and those of the different cations with the enzyme molecule, the artificial substrate p-nitrophenylphosphate was utilized. Kinetic studies of the activation of acid phosphatase (phosphorylcholine phosphatase) mediated by divalent cations Mg2+, Zn2+ and Cu2+ revealed that all these ions bind to the enzyme in a compulsory order (ordered bireactant system). The Km values obtained for p-NPP in the presence of Mg2+, Zn2+ and Cu2+ were 1.4 mM, 1.0 mM and 3.5 mM, respectively. The KA values for the same ions were 1.25 mM, 0.05 mM and 0.03 mM, respectively. The Vmax obtained in the presence of Cu2+ was about twofold higher than that obtained in the presence of Mg2+ or Zn2+. The inhibition observed with Al3+ seems to be a multi-site inhibition. The K'app and n values, from the Hill plot, were about 0.25 mM and 4.0 mM, respectively, which were independent of the metal ion utilized as activator. It is proposed that the acid phosphatase may exert its action under physiological conditions, depending on the availability of either one of these metal ions.
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PMID:Pseudomonas aeruginosa acid phosphatase. Activation by divalent cations and inhibition by aluminium ion. 154 81

Heavy metals including mercury, cadmium, cobalt, and copper (100 microM) exerted an adverse effect on the viability of isolated rat adrenal capsular (zona glomerulosa), adrenal decapsular (fasciculata and reticularis), and Leydig cells of the testis, with mercury being the most potent. Due to the decreased cell viability there was a parallel reduction in corticotropin-stimulated corticosterone production by adrenal decapsular cells and luteinizing hormone-stimulated testosterone production by Leydig cells. The results indicated a direct toxic action of these heavy metals on steroid-producing cells in the adrenal gland and the testis. Other metals tested, including lead, zinc, aluminum, chromium, iron, nickel, and lithium, did not exert any deleterious effect on cell viability or hormone-induced steroidogenesis in adrenal and Leydig cells when tested up to a concentration of 100 microM.
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PMID:Toxic effect of heavy metals on cells isolated from the rat adrenal and testis. 215 92

Endogenous opioids (EO) probably do not modulate endotoxin (LPS)- or interleukin 1 (IL1)-induced fever because naloxone does not prevent its development. Yet, increases in CSF and hypothalamic levels of beta-endorphin have been reported during LPS-and IL1-induced fevers. Since IL1 also reduces the specific binding of opioids to their receptors in guinea pig brain, the opioids could be involved in modulating nonfebrile effects of IL1. To determine whether EO might have a role in the IL1-induced acute-phase glycoprotein response of guinea pigs, (1) naloxone (5 and 10 mg/kg, SC) was injected prior to LPS (S. enteritidis 2 micrograms/kg, IV; N = 5), and (2) morphine (MOR, 10 micrograms/microliter), [D-ala2]-met-enkephalinamide (DAME, 5 micrograms/microliter), or dynorphin A (DYN, 5 micrograms/microliter) was injected into the preoptic area (1 microliter, bilaterally; N = 8/treatment) or into the 3rd ventricle (N = 4/treatment); pyrogen-free saline was the control injection. Measurements were: core temperature (Tco) and, as indices of acute-phase glycoproteins, plasma levels of copper (Cu) and N-acetylneuraminic acid (NANA). Naloxone did not prevent the fever or the increases in plasma Cu and NANA levels evoked by LPS. The intracerebral administration of opioid agonists by either route induced variable rises in Tco, each with a different pattern, but no increases in plasma Cu and NANA levels. Thus, EO do not participate in the central modulation of acute-phase glycoprotein synthesis, but may have a role in influencing other nonthermal IL1 effects in the CNS.
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PMID:Hypothalamic opioids and the acute-phase glycoprotein response in guinea pigs. 241 70

Normal human melanocytes, unlike malignant melanoma cells, required at least three growth-promoting agents, i.e., phorbol ester for protein kinase C activation and the growth factors basic fibroblast growth factor (bFGF) and insulin, for growth in chemically defined W489 medium. Cell growth was further stimulated by addition of agents that increase intracellular levels of cyclic adenosine 3',5'-monophosphate (cAMP) to the medium. Among these agents, the pituitary hormones alpha-melanocyte-stimulating hormone (alpha-MSH) and follicle-stimulating hormone were the most potent, whereas bacterial toxins, including cholera, tetanus, and pertussis toxin and their subunits either were less mitogenic or gave variable results depending on the culture tested. Medium containing phorbol ester PMA, growth factors bFGF and insulin (or insulin-like growth factor-I), and synthetic alpha-MSH supported melanocyte growth for more than 5 months with doubling times between 5 and 8 days. Two copper-binding proteins, ceruloplasmin and tyrosinase, were mitogenic when added to medium and ceruloplasmic induced a long bi- to tripolar-shape of cells. Addition of 1 mM dibutyryl cAMP to the medium led to the formation of dendrites in all cells, with an average of 28 extensions per cell. Although cell growth was inhibited by dibutyryl cAMP, cells were not terminally differentiated and continued to proliferate. Dendritic melanocytes showed a 2.2-fold increase in activity of the tyrosine kinase pp60c-src. The induction of dendritic processes in melanocytes by dibutyryl cAMP or sodium butyrate was reversible and appears to reflect the expression of the mature melanocytic phenotype in situ.
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PMID:Regulatory factors that determine growth and phenotype of normal human melanocytes. 246 9

N alpha-Acetyltransferase, which catalyzes the transfer of an acetyl group from acetyl coenzyme A to the alpha-NH2 group of proteins and peptides, was isolated from Saccharomyces cerevisiae and demonstrated by protein sequence analysis to be NH2-terminally blocked. The enzyme was purified 4,600-fold to apparent homogeneity by successive purification steps using DEAE-Sepharose, hydroxylapatite, DE52 cellulose, and Affi-Gel blue. The Mr of the native enzyme was estimated to be 180,000 +/- 10,000 by gel filtration chromatography, and the Mr of each subunit was estimated to be 95,000 +/- 2,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme has a pH optimum near 9.0, and its pI is 4.3 as determined by chromatofocusing on Mono-P. The enzyme catalyzed the transfer of an acetyl group to various synthetic peptides, including human adrenocorticotropic hormone (ACTH) (1-24) and its [Phe2] analogue, yeast alcohol dehydrogenase I (1-24), yeast alcohol dehydrogenase II (1-24), and human superoxide dismutase (1-24). These peptides contain either Ser or Ala as NH2-terminal residues which together with Met are the most commonly acetylated NH2-terminal residues (Persson, B., Flinta, C., von Heijne, G., and Jornvall, H. (1985) Eur. J. Biochem. 152, 523-527). Yeast enolase, containing a free NH2-terminal Ala residue, is known not to be N alpha-acetylated in vivo (Chin, C. C. Q., Brewer, J. M., and Wold, F. (1981) J. Biol. Chem. 256, 1377-1384), and enolase (1-24), a synthetic peptide mimicking the protein's NH2 terminus, was not acetylated in vitro by yeast acetyltransferase. The enzyme did not catalyze the N alpha-acetylation of other synthetic peptides including ACTH(11-24), ACTH(7-38), ACTH(18-39), human beta-endorphin, yeast superoxide dismutase (1-24). Each of these peptides has an NH2-terminal residue which is rarely acetylated in proteins (Lys, Phe, Arg, Tyr, Val, respectively). Among a series of divalent cations, Cu2+ and Zn2+ were demonstrated to be the most potent inhibitors. The enzyme was inactivated by chemical modification with diethyl pyrocarbonate and N-bromosuccinimide.
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PMID:Purification and characterization of an N alpha-acetyltransferase from Saccharomyces cerevisiae. 284 92

Twenty-four male subjects participated in a study in which the effect of feeding diets low in copper (1.03 mg/day) on plasma opiates was determined. The subjects were fed a low-copper diet for 11 wk with either starch or fructose as a major source of carbohydrate. Feeding low-copper diet decreased serum copper level significantly. In addition, plasma leu- and met-enkephalins decreased significantly while beta-endorphin levels rose. On repletion with copper (3 mg/day) for 3 wk, plasma enkephalins increased while beta-endorphin levels decreased to pretest values. These results suggest that feeding low copper decreases plasma enkephalins, which may reflect a copper-dependent process affecting enkephalin biosynthesis and/or release.
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PMID:Decreased plasma enkephalins in copper deficiency in man. 293 71

Peptidylglycine alpha-amidating activities from rat pituitary, brain and small intestine were compared, utilizing C-terminal analogues of vasoactive intestinal polypeptide (VIP), D-Tyr-Leu-Asn-Gly and D-Tyr-Asn-Gly, and C-terminal analogue of alpha-MSH, D-Tyr-Val-Gly. The three tissues had enzymic activities capable of converting the glycine-extended peptides to the corresponding alpha-amidated ones. In other words, all of three peptides could serve as substrates for the enzymes from both neural and gastrointestinal tissues. The activities were stimulated in the presence of copper and ascorbate; the optimal concentration of each cofactor was roughly equal for the three enzymes; similar pH profiles (a neutral pH optimum at 6.5-7 and another one at 8-8.5) were also observed. Desamide VIP-Gly was proved to be a potent inhibitor of the alpha-amidating activities from the tissues, but VIP was not, indicating that the alpha-amidating enzymes from these tissues in common have a recognition site for the C-terminal glycine of the glycine-extended precursor regardless of the length and nature of the sequence. No fundamental differences were observed between the catalytic properties of the alpha-amidating activities from these three tissues, raising the possibility that similar enzymes, which may or may not be a single species, are functioning in tissues that produce alpha-amidated polypeptides in vivo.
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PMID:Characterization of peptidylglycine alpha-amidating activities in rat pituitary, brain and small intestine using glycine-extended C-terminal analogues of vasoactive intestinal polypeptide as substrate. 323 97

A statistical correlationl was made between adrenocorticotropin (ACTH) and four elements in rats under control, stress, and stress-recovery conditions. Blood serum zinc showed a strong positive correlation with the rise in ACTH during stress and its decline in stress recovery. Serum calcium, copper, and magnesium demonstrated little correlation with ACTH changes. The strong ACTH-zinc correlation points to an as yet undefined interaction between ACTH and zinc
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PMID:Mineral element correlation with adenohypophyseal-adrenal cortex function and stress. 432 80

Recent amino acid sequence data suggest that trypsin-like and carboxypeptidase B-like activities are required for the processing of pituitary prohormones--e.g., pro-opiocortin (pro-adrenocorticotropin/lipotropin) and provasopressin in secretory granules. In this study the existence of a carboxypeptidase B activity in purified secretory granules from anterior, intermediate, and neural lobes of rat pituitary has been examined. A carboxypeptidase B activity that cleaved the COOH-terminal -Lys-Lys-Arg residues from the adrenocorticotropin fragment ACTH-(1-17) (a potential hormone product liberated from pro-opiocortin by a trypsin-like enzyme) was detected in anterior and intermediate lobe granules. A similar carboxypeptidase B activity was also present in purified secretory granules from rat pituitary neural lobes that cleaved the -Lys-Arg residues from [Arg8]vasopressin-Gly-Lys-Arg, a potential product cleaved from provasopressin. Secretory granule carboxypeptidase(s) from the three lobes of the pituitary was shown to cleave 125I-[Met]enkephalin-Arg6 to form 125I-[Met]enkephalin as well. 125I-[Met]Enkephalin was used as a model substrate for the quantitative assay of pituitary carboxypeptidase activity. The carboxypeptidase B in secretory granules from all three lobes was shown to be active at pH 5.5, but not at pH 7.4. Inhibition by the zinc metallocarboxypeptidase inhibitors guanidinopropylsuccinic acid, aminomercaptosuccinic acid, benzylsuccinic acid, 2-mercaptomethyl-3-guanidinoethylthiopropanoic acid, and the potato carboxypeptidase B inhibitor, and inhibition by the metal chelators EDTA and 1,10-phenanthroline demonstrate metal ion dependence of the pituitary granule carboxypeptidase activities. However, Co2+ stimulated the secretory granule carboxypeptidase B activities. Thiol protease inhibitors such as Cu2+ and p-chloromercuriphenylsulfonic acid also inhibited the activity. Thus, the secretory granule carboxypeptidase B-like activities in all three lobes of the pituitary appear to be similar thiol-metallopeptidases that differ from other carboxypeptidase activities previously described and may play an exclusive role in hormone biosynthesis in the pituitary.
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PMID:Carboxypeptidase B-like converting enzyme activity in secretory granules of rat pituitary. 632 44

A location of copper and zinc- superoxide dismutase (Cu, Zn-SOD) in adenohypophysis and pituitary adenomas was examined with immunohistochemical technique. Pituitary adenomas include thirteen functioning, five nonfunctioning; functioning adenomas consist seven prolactinomas, four growth hormone (GH) secreting, two adrenocorticotropic hormone (ACTH) secreting adenomas. Three specimens of normal adenohypophysis were used for control study. The Cu, Zn-SOD was localized diffusely in the cytoplasm of normal adenohypophyseal cells and the tumor cells. Sometimes immunoreactive products of Cu, Zn-SOD revealed in the cytoplasm of endothelial cell, neutrophil, macrophage and the cell membrane of erythrocyte in the vessels. The content of Cu, Zn-SOD in normal adenohypophyseal cells and pituitary adenomas was markedly higher in normal cells than adenoma cells. No significant difference of the SOD content was observed not only in non-functioning adenoma but also in functioning adenoma cells including PRL, GH and ACTH cells.
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PMID:[Immunohistochemical study on the expression of copper and zinc-superoxide dismutase (Cu, Zn-SOD) in human adenohypophysis and pituitary adenomas]. 782 10


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