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)

The effects of temperature on adenylate cyclase (AC) activity from rat white adipocytes were studied. Arrhenius plots of the data were found to be biphasic for basal AC activity, with a break near 27 degrees C. Noradrenaline and corticotropin induced a shift in the break with a rise in energy of activation (Ea) on both sides of the break. Aabove break point only, Ea increased with respect to hormone does as a hyperbolic function. The maximum value was in the range 17-21 Kcal x mol-1. Temperature was shown to have only a slight effect on the binding capacity of corticotropin to its receptor sites. The possibility of the existence of multiple thermodynamic states for the enzyme is envisaged. Basal AC activity is thermodynamically different from the hormone-stimulated enzyme. Hormones induce changes in the basal conformation of the enzyme, and this is reflected in modifications of Arrhenius plots. The maximal state of activation reached with high doses of hormones could be interpreted as a 'desensitization' of enzyme and/or enzyme systems to membrane lipid interactions.
Mol Cell Endocrinol 1977 Jun
PMID:Temperature dependence of adenylate cyclase activity from rat white adipocytes. 1 77

1. A human cancer cell line (COLO 16) derived originally from an epidermal squamous cell carcinoma was found to possess adenylate cyclase responsiveness to beta-adrenergic agonists. 2. The adenylate cyclase response was characterized with respect to activation constants (KA) for various beta-adrenergic agonists and inhibition constants (Ki) for antagonists. 3. Intact cells responded with dose-dependent increases in production of cyclic adenosine 3':5'-monophosphate. 4. Properties of the beta-adrenergic receptor were evaluated by using the specific binding of [3H]propranolol to cell membranes. Specific binding was saturable, with KD 5.79 nmol/l and binding sites 0.68 pmol/mg of protein. 5. Competition for binding to cell membranes was shown by beta-adrenergic agonists and antagonists and was stereospecific. There was close agreement between the affinity of these various agents on adenylate cyclase and receptor binding. 6. It is likely that the beta-adrenergic receptor-linked adenylate cyclase in COLO 16 cells represents persistence in a cancer cell line of a receptor present normally in epidermal cells.
Clin Sci Mol Med 1978 Jul
PMID:Characterization of beta-adrenergic receptor linked to adenylate cyclase in a human cancer cell line (COLO 16). 2 27

This short review summarizes some of the data concerning the regulation of adrenocortical adenylate cyclase by ACTH and other putative effectors, such as guanosine and nucleotides, divalent cations and adenosine. The available information on ACTH-sensitive adenylate cyclase of the adrenal cortex is discussed in comparison to other cyclase systems and the possible biochemical mechanisms of action of ACTH on the adrenal cortex.
Mol Cell Endocrinol 1979 Feb
PMID:The regulation of adenylate cyclase of the adrenal cortex. 3 14

1. The activities of some membrane-bound enzymes such as adenylate cyclase, Na+ + K+-stimulated adenosine triphosphatase (Na+ + K+-ATPase), Ca2+-stimulated ATPase and Mg2+-stimulated ATPase were examined in heart sarcolemmal fractions from control and cardiomyopathic hamsters at different stages of heart failure. 2. The basal adenylate cyclase activity in sarcolemma from cardiomyopathic animals with early, moderate and late stages of heart failure was not different from the control values whereas the sodium fluoride- and catecholamine-stimulated adenylate cyclase activities were depressed in cardiomyopathic sarcolemma at moderate and late stages. 3. The sarcolemmal Na+ + K+-ATPase activity was decreased and the non-specific phosphatase activity was increased at early, moderate and late stages of heart failure. 4. The sarcolemmal Ca2+-ATPase activity was decreased at moderate and late stages whereas the Mg2+-ATPase activity was decreased at the late stages of heart failure only. 5. A marked decrease was found in calcium binding by heart sarcolemma from cardiomyopathic hamsters at late stages of failure. 6. These results suggest that dramatic sarcolemmal changes are associated with heart failure, and support the view that membrane abnormalities play a crucial role in the development of myocardial dysfunction, cyclase, calcium binding, heart failure, heart membranes, sarcolemmal enzymes.
Clin Sci Mol Med 1976 Sep
PMID:Comparison of heart sarcolemmal enzyme activities in normal and cardiomyopathic (UM-X7.1) hamsters. 13 61

Partially purified, non-suppressible, insulin-like material (NSILA-S) was studied with respect to its effect on the levels of 3',5'-cyclic adenosine monophosphate (cAMP) and its mechanism of action in the control of this nucleotide in rat fat cells. NSILA-S prevents the rise of cAMP in fat cells under the influence of isoproterenol with similar kinetics to insulin. A maximal effect is observed at about 70 ng/ml with a biological activity equivalent to 200 muU/ml of insulin. NSILA-S inhibits norepinephrine-stimulated adenylate cyclase activity in fat cell ghosts and partially purified plasma membrane preparations. At 10 mM Mg2+, the inhibition is characterized by an effect of Vmax without change in affinity towards ATP (apparent KM 30 muM). Similarly there is no observed change in affinity towards Mg2+. With respect to inhibition of norepinephrine-stimulated adenylate cyclase, the dose-response curve of NSILA-S is similar to that already found with intact cells. The effect of norepinephrine is inhibited throughout the dose-response range between 5 X 10(-7) and 5 X 10(-4) M. In contrast to previous observations with insulin in ghosts, NSILA-S inhibits the basal adenylate cyclase activity. Cyclic nucleotide phosphodiesterase activity in homogenates as measured at 1.0 muM substrate is increased by 90% after previous incubation of fat cells with NSILA-S. The study suggests that the anti-lipolytic effect of NSILA-S is mediated by a lowering of cAMP through inhibition of the adenylate cyclase and/or stimulation of the phosphodiesterase system.
Mol Cell Endocrinol 1975 Oct
PMID:Effect of partially purified NSILA on adenylate cyclase, phosphodiesterase and 3',5'-cyclic AMP in fat cells. 17 93

LH- and FSH-sensitive adenylate cyclase activity was present in homogenates of whole testis tissue as well as in microdissected seminiferous tubules derived from young rats. In homogenates of seminiferous tubules a single adenylate cyclase appears to interact with both LH and FSH through separate hormone-specific receptors. Disruption of testis tissue by homogenization exposes functional FSH and LH receptors which are inaccessible to the hormones in intact cell preparations. These results indicate that in certain seminiferous tubule cell types only a fraction of the total functional receptors present is accessible to the cell surface for interaction with hormone.
Mol Cell Endocrinol 1976 Feb
PMID:LH- and FSH-stimulating of adenylate cyclase in seminiferous tubules from young rats: functional FSH and LH receptors unmasked by homogenization. 17 66

ACTH stimulated steroidogenesis and cAMP (adenosine 3',5'-monophosphate) accumulation in an adrenocortical mouse tumor cell line (clone Y1) with Kd values which differed by more than one order of magnitude (5.2 X 10(-11) M and 7 X 10(-10) M, respectively). All of the cAMP formed in response to added ACTH appeared extracellularly in 5- or 30-min incubations. ACTH, at 5 and 10 muU/ml, stimulated steroidogenesis to 25% and 40% of maximum activity; and increased the extracellular accumulation of cAMP 1.4-fold and 2.3-fold, respectively. The effects of ACTH appeared to be via an action on intracellular ATP, specific for cAMP and dependent on an ACTH-sensitive adenylate cyclase system. These observations indicate that ACTH increases cAMP accumulation in Y1 cells at virtually all steroidogenic concentrations and suggest that cAMP is an essential component of ACTH-stimulated steroidogenesis.
Mol Cell Endocrinol 1976 Mar
PMID:Steroidogenesis and extracellular cAMP accumulation in adrenal tumor cell cultures. 17 21

The development of adenylate cyclase responsiveness to vasopressin and parathyroid hormone was studied using membrane fractions prepared from medullo-papillary and cortical portions of kidneys of 2-46-day-old rats. The development of vasopressin binding capacity was followed on the same preparations, using [3H]vasopressin. The characteristics of medullo-papillary adenylate cyclase response to vasopressin were identical in young and adult control animals as regards apparent Km values for [Lys8]vasopressin (3 X 10(-8) M), specificity towards the natural neurohypophysial peptides and the effects of Mg2+. However, the magnitude of maximal enzyme activation by vasopressin was much lower in very young than adult animals. Accordingly vasopressin responsiveness increased sharply between the 10th and 25th days but the magnitude of the maximal response only reached the adult value between the 30th and 45th days after birth. During both periods basal adenylate cyclase activity was almost independent of age. Specific vasopressin binding sites were detected on kidney medullo-papillary membranes from young animals. Vasopressin binding capacity and adenylate cyclase responsiveness to the hormone followed similar development patterns. However, the appearance of specific binding sites slightly preceded the onset of adenylate cyclase responsiveness. Basal cortical adenylate cyclase activity/mg protein was 12 times higher in 2-day-old rats than in the adult controls. It dropped with age but only fell to the adult value between the 25th and the 35th days after birth. For the youngest animals tested (2 days old), the increase in activity due to parathyroid hormone was about half the increase measured in adults, and gradually rose to about 75% of the adult response between the 2nd and 46th days after birth. Apparent Km values for parathyroid hormone were identical in young and adult animals (3.2 and 3.0 U/ml, respectively).
Mol Cell Endocrinol 1976 Mar
PMID:Ontogenic development of antidiuretic hormone receptors in rat kidney: comparison of hormonal binding and adenylate cyclase activation. 17 22

A mutational alteration either in adenylate cyclase (cya-) or in cyclic-3'5'-AMP (cAMP) receptor protein (crp-) rendered Salmonella typhimurium incapable of producing flagella. The amount of mRNA specific for flagellin in these mutants was almost negligible when assayed in an in vitro protein synthesizing system. A secondary mutation cfs, partially suppressing the cya- mutation, was identified among the revertants of cya-. A mutation in the same cistron as cfs resulted in a non-flagellate phenotype either by itself or in combination with cfs. The cistron, which was given the gene symbol flaT, was located between flaE and flaL. It was suggested that cAMP receptor protein together with cAMP modulates the gene flaT, which in turn acts as a positive effector on the synthesis of active mRNA specific for flagellin.
Mol Gen Genet 1976 Dec 31
PMID:The role of cAMP in flagellation of Salmonella typhimurium. 17 91

1. The diphosphonates, disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP) and disodium dichloromethylene diphosphonate (Cl2MDP), inhibit bone resorption in animals and in explanted bone in tissue culture. The possibility that these effects might be due to inhibition of skeletal adenylate cyclase has been studied. 2. EHDP and Cl2MDP, added for 30 min to the incubation medium at concentrations known to inhibit bone resorption, had no effect on basal content of adenosine 3':5'-cyclic monophosphate (cyclic AMP) of mouse calvaria incubated in vitro, nor did they inhibit the rise in cyclic AMP induced by bovine parathyroid hormone. 3. Pretreatment of mice for 3 days with Cl2MDP also had no effect on cyclic AMP under basal conditions or after incubation of explanted calvaria with parathyroid hormone in vitro. EHDP under similar conditions slightly inhibited the increase induced by parathyroid hormone but had no effect on basal concentrations of cyclic AMP. 4. It is suggested that the inhibition of adenylate cyclase is not an essential feature of the reduction of bone resorption by diphosphonates, which may act by direct inhibitory effects on the dissolution of hydroxyapatite and perhaps by other unidentified effects on bone cells. Key words: adenosine 3':5'-cyclic monophosphate, bone, dichloromethylene diphosphonate, diphosphonates, ethane-1-hydroxy-1,1-diphosphonate, parathyroid hormone.
Clin Sci Mol Med 1976 Jun
PMID:Effect of diphosphonates on adenosine 3':5'-cyclic monophosphate in mouse calvaria after stimulation by parathyroid hormone in vitro. 17 50


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