Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three temperature-sensitive mutant strains for RNA polymerase beta or beta' subunits (carrying mutations tsx, A2R7 and R120) were used in order to investigate the dependence of the induced lac expression on stimulation by cyclic AMP after the shift to non-permissive temperature. High temperature lowered the rate of beta-galactosidase synthesis. However, the low rate of synthesis could be strongly increased by cyclic AMP (30, 2.4 and 5.7-fold increases for tsX, A2R7 and R120 mutants, respectively). At the permissive temperature stimulation by cyclic AMP was less than 1.4-fold (minimal medium supplemented with glycerol). The results suggest that the maximal expression of the lac operon is saturated, that is, a hypothetical increase in RNA polymerase or cAMP-CRP concentration in the cell with not enhance the expression. The concept of saturation explains why it was possible to increase the beta-galactosidase synthesis in conditions of limited promoter binding activity of RNA polymerase through increase in concentration of cyclic AMP-CRP complex in the cell (addition of cyclic AMP) to the values higher than that observed on glycerol.
Mol Gen Genet 1979 Jun 20
PMID:Expression of the lac operon in RNA polymerase mutants of Escherichia coli K12. 22 41

Cyclic AMP-dependent protein kinase has been well established to be composed of catalytic and regulatory subunits, and cyclic AMP acts to dissociate these subunits to exhibit full enzymatic activity. In contrast, cyclic GMP-dependent protein kinase does not possess such a subunit structure and is activated by cyclic GMP simply in an allosteric manner. In addition to cyclic AMP-dependent and cyclic GMP-dependent protein kinases, another species of multifunctional protein kinase has been found in many mammalian tissues. This protein kinase is entirely independent of cyclic nucleotides and activated by lower concentrations of Ca2+ in the presence of a membrane-associated factor. This factor has been identified as phospholipids; in fact, phosphatidylinositol and phosphatidylserine are active in this role, whereas lecithin and sphingomyelin are unable to activate the enzyme. Thus, the three species of protein kinases mentioned above are activated in different manners. Nevertheless, these enzymes show very similar substrate specificities and phosphorylate the same specific seryl residues of histone fractions. In addition, all enzymes have abilities to activate and inactivate muscle phosphorylase kinase and glycogen synthetase, respectively, although the relative rates of reactions towards various substrates are markedly different. The Ca2+-dependent protein kinase seems to be associated with membranous components, whereas cyclic GMP-dependent protein kinase appears to be related to certain subcellular organella such as nucleus. Suggestive evidence is available implying that the cyclic AMP-, cyclic GMP- and Ca2+-activated three sets of protein kinase systems may play each specific physiological roles presumably owing to their own subcellular compartments.
Mol Cell Biochem 1979 Feb 09
PMID:Regulatory and functional compartment of three multifunctional protein kinase systems. 22 57

In a previous report we have shown that insulin increases the phosphorylation of an endogenous protein of mol. wt. 16 000 daltons in sarcolemma membranes. In the present work we have demonstrated that phosphorylations of exogenous histones by the sarcolemma membranes are also increased by insulin. These results indicate that insulin activates a cyclic-AMP-independent protein kinase in sarcolemma membranes. The stimulatory effect of insulin on protein phosphorylations is increased by GTP and its analogue GMP-P(NH)P. The insulin effect was increased 3--4-fold by micromolar concentrations of GTP. The effect by the analogue GMP-P(NH)P was somewhat less. In the absence of insulin guanosine nucleotides had no effect on phosphorylation of the proteins. The results suggest that GTP is a modulator in the activation of a sarcolemma membrane protein kinase by insulin.
Mol Cell Endocrinol 1979 Oct
PMID:The effect of insulin and guanosine nucleotides on protein phosphorylations by sarcolemma membranes from skeletal muscle. 22 62

Specific radioimmunoassays (RIAs) for ACTH, beta-endorphin, alpha-MSH and beta-MSH were used to identify the immunoreactive components released during incubation of rat anterior pituitary cells in primary culture. Such measurements were performed after separation of the incubation media by chromatography on Sephadex G-50 or G-75. The ACTH-RIA measured approximately equal amounts of 13 and 4.5K ACTH while equal proportions of components migrating at the position of beta-LPH and beta-endorphin were measured in the beta-endorphin RIA system. Immunoreactive components migrating at the position of gamma-LPH and alpha-MSH were measured in the beta-MSH and alpha-MSH RIA systems, resp. 3 purified corticotropin-releasing fractions (CRF) prepared from porcine hypothalami and increasing concentrations of N6,O2'-dibutyryl cyclic AMP and theophylline led to parallel release of ACTH, beta-endorphin, beta-MSH and alpha-MSH immunoreactivities while preincubation with dexamethasone led to a 30-60% inhibition of the release of all peptides. The present data show that the release of ACTH, beta-LPH, beta-endorphin, gamma-LPH and alpha-MSH-like immunoeactivities occurs in parallel in anterior pituitary cells in culture both under basal and acute stimulatory or inhibitory conditions of release.
Mol Cell Endocrinol 1979 Nov
PMID:Parallel release of ACTH, beta-endorphin, alpha-MSH and beta-MSH-like immunoreactivities in rat anterior pituitary cells in culture. 22 47

Calcium, in partnership with cyclic AMP, controls the proliferation of non-tumorigenic cells in vitro and in vivo. While it does not seem to be involved in the proliferative activation of cells such as hepatocytes (in vivo) or small lymphocytes (in vitro), it does control two later stages of prereplicative (G1) development. It must be one of the very many regulatory and permissive factors affecting early prereplicative development, because severe calcium deprivation reversibly arrests some types of cell early in the G1 phase of their growth-division cycle in vitro. However, calcium more specifically and much more often regulates a later (mid or late G1) stage of prereplicative development. Thus, regardless of its severity or the type of cell, calcium deprivation in vitro or in vivo reversibly stops proliferative development at that part of the G1 phase in which the cellular cyclic AMP content transiently rises and the synthesis of the four deoxyribonucleotides begins. The evidence points to calcium and the cyclic AMP surge being co-generators of the signal committing the cell to DNA synthesis. The evidence is best explained so far by the cyclic AMP surge causing a surge of calcium ions which combine with molecules of the multi-purpose, calcium-dependent, regulator protein calmodulin (CDR) somewhere between the cell surface and the cytosol. The resulting Ca-calmodulin complexes then stimulate many different (and possibly membrane-associated) enzymes such as protein kinases, one of which produces the DNA-synthetic initiator. Calcium has little or no influence on the proliferation of tumor cells. Some possible explanations of this very important loss of control are considered.
Mol Cell Biochem 1979 Nov 01
PMID:The regulation of cell proliferation by calcium and cyclic AMP. 22 7

Thyrotropin (TSH) secretion from isolated anterior pituitary cells has been studied using the technique of cell column perifusion. The consistency in secretory rate and temporal profiles of TSH output in response to stimulation illustrated that the system is suitable for studying the kinetics of stimulation and inhibition of secretion. During perfusion TSH release was stimulated in response to a variety of secretogogues, namely TRH, raised potassium concentrations and phosphodiesterase inhibitors. The onset and termination of the secretory responses were rapid and displayed a temporally biphasic pattern of secretion. Dose-related increases in TSH output in response to TRH and consistent responses to repetitive pulses of TRH (5.5 X 10-10 M) during a 4 h period were demonstrated. Studies on the dynamics of thyroid hormone feedback on TRH-stimulated TSH secretion indicated that inhibition was manifest within 1 h and reached a maximum after 2 1/2 h during continual exposure to thyroid hormones. Isobutylmethylxanthine (IBMX) potentiated the effect of raised K+ as well as that of TRH on TSH secretion, suggesting an as yet unidentified relationship between Ca2+ and cyclic AMP.
Mol Cell Endocrinol 1977 Oct
PMID:Studies on the control and dynamics of thyrotropin secretion from isolated adenohypophyseal cells. 41 4

Glucose-6-phosphate dehydrogenase was purified to homogeneity from testes and kidneys of the inbred strain of mice (DBA/2J) by a simple two-step affinity column procedure. This involved the sequential application of 8-(6-aminohexyl)-amino-AMP- and -2', 5'-ADP-Sepharose columns and biospecific elution with NADP+ in both steps. The molecular and biochemical properties of the purified enzyme were studied in detail. These include the molecular weight determination, amino acid composition, steady-state kinetics, inactivation by high temperature, urea and iodoacetate, and immunology. The purified enzyme from mouse kidneys or testes was shown to be a tetramer with a molecular weight of 220,000. The enzyme is highly specific for glucose-6-phosphate, exhibits almost no activity with NAD+ as a coenzyme and is little inhibited by AMP or ATP. Michaelis constants for glucose-6-phosphate and NADP+ were determined to be 50 microM and 10 microM respectively. NADPH is a competitive inhibitor of NADP+ and has a Ki of 18 microM. Rabbit antisera against glucose-6-phosphate dehydrogenase were raised. The antisera also cross-react with the same enzyme from human and guinea pig.
Mol Cell Biochem 1979 Mar 19
PMID:Purification and characterization of mouse glucose 6-phosphate dehydrogenase. 46 Jan 73

A method for determining the equilibrium constant of sin-anti-states in the aqueous solution of purine and pyrimidine nucleotides and nucleosides has been proposed. This method is based on the measurement of the spin-lattice relaxation rate of H(1') atom of purine nucleotides before and after exchange of H(8) deuterium in the case of purine nucleotides or H(1') and H(5) atoms of pyrimidine nucleotides. The results obtained were interpreted by the two-state dynamic model. The method applied for investigation of the conformation situation in solutions of Ado, 5'-AMP, 3'-AMP, 5'-CMP and 3'-CMP. 5'-AMP and 5'-CMP were shown to exist predominantly in the anti-state (90%). In the case of 3'-nucleotides the enhancement of the relativity weight of sin-populations to 0.2 and 0.85 for 3'-CMP and 3'-AMP, respectively, was found. In the solution Ado both anti- and sin-state were equiprobable. Experimentally measured relaxation rates of H(8) of adenine or H (6) of cytosine nucleotides were used for determination of the time average orientation of nucleic bases towards the ribose ring in the anti-state. For all compounds investigated with the exception of 3'-AMP the "normal" anti-conformation was confirmed. The 3'-AMP was found to be characterized by high anti-conformation. The probable causes of the conformational situation organization and correlation between the N/S and sin/anti rations are discussed.
Mol Biol (Mosk)
PMID:[Conformation of nucleotides, oligonucleotides and their analogues in aqueous solution. II. Syn-anti-equilibrium in solutions of adenosine, 5'-AMP, 3'-AMP, 5'-CMP and 3'-CMP]. 47 Sep 43

Cytoplasmic and mitochondrial isozymes of NADP+-dependent isocitrate dehydrogenase were purified from kidney and heart tissue of an inbred strain of mice. The cytoplasmic isozyme was purified from kidney of DBA/2J mice by means of a four-step procedure which included affinity chromatography with an 8-(6-aminohexyl)-amino-NADP+-Sepharose column. The heart mitochondrial isozyme of DBA/2J mice was purified by a two-step procedure involving the use of 8-(6-aminohexyl)-amino-AMP-Sepharose and 8-(6-aminohexyl)-amino-NADP+-Sepharose columns. The specific activity of the homogeneous cytoplasmic and mitochondrial isozymes was 40 units/mg and 45 units/mg, respectively. Native and subunit molecular weights of these two isozymes were determined by chromatography on Sephadex G-100, G-150 and G-200 Superfine and polyacrylamide gel electrophoresis. Both isozymes were found to be dimers with the subunit molecular weight of approximately 35,000. The sedimentation coefficients were determined to be 5.9 and 6.1 for the mitochondrial and cytoplasmic isozyme, respectively. The amino acid compositions of these two isozymes revealed distinct differences in arginine and proline contents. A modified procedure regarding the use of affinity columns for the purification of the weakly bound enzymes is also discussed.
Mol Cell Biochem 1979 Feb 09
PMID:Purification and structural properties of isozymes of isocitrate dehydrogenase from the mouse. 48 28

Using quantitative gel filtration techniques partition coefficients, Kp-values, have been determined between aqueous cationic micellar hexadecyltrimethylammonium bromide, CTAB, and several biomonomer. Kp-values for 5'-adenylic acid, 5'-cytidylic acid, 5'-guanylic acid, 5'-uridylic acid and 5'-thymidylic acid are 1,400 +/- 150. Nucleotides bind to CTAB micelles effectively, but nonselectively. Conversely, the binding of tRNAs to micellar CTAB is selective. Kp-values for glutamic acid II, tyrosine and phenylalanine tRNAs (in 1.0MNaCl) are 520, 3,100 and 5,600, respectively. Kp-values for the binding of alanine, arginine, aspartic acid, glutamic acid, glycine, histidine, phenylalanine, serine, threonine and tryptophan to micellar CTAB are less than 8. Conversion of unitless Kp-values for the binding of amino acids, nucleotides and nucleosides to both anionic and cationic micelles, to K (in 1/g) values allows the comparison of clays and micelles as prebiotic concentrating media. Using correlations between surface densities of the biomonomers and their binding constants, it is shown that aqueous micelles (at pH = 8) are a better concentrating media than are clays.
J Mol Evol 1977 Dec 29
PMID:Partitioning of amino acids and nucleotides between water and micellar hexadecyltrimethylammonium halides. The prebiotic significance of cationic surfaces. 59 74


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