Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.6.1.1 (adenylate cyclase)
19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several vasopressin analogues were tested on pig kidney membranes for their ability to activate adenylate cyclase and to inhibit the binding of [8-lysine]vasopressin. Both the adenylate cyclase activation and hormonal binding were measured on the same enzyme preparation and under identical were measured on the same enzyme preparation and under identical experimental conditions. A preincubation period in the presence of hormone allowed the binding process to reach equilibrium. Peptide concentrations causing half-maximal adenylate cyclase activation (apparent Km) were, in the order of decreasing affinity:2.5 to 7.0 to 7.0 times 10-10 M [8-lysine] vasopressin, 3.1 to 4.0 times 10-9 M [8-arginine] vasopressin, 2.0 to 3.0 times 10-9 M [I,6-alpha-deaminocystathionine, 8-ornithine]vasopressin, 3.1 times 10-7 M des-9-glycineamide[8-lysine]vasopressin, 0.5 to 1.0 times 10-6 M[1,6-alpha-deaminocystathionine, 2-0-tert...
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PMID:Vasopressin-sensitive kidney adenylate cyclase. Structural requirements for attachment to the receptor and enzyme activation: studies with vasopressin analogues. 16 61

Adenylate cyclase and the [8-lysine]vasopressin receptor were solubilized from pig kidney medulla membranes using the nonionic detergent Triton X-100. Optimal conditions for solubilization were under continuous stirring in a medium containing 0.5% (/v) Triton X-100, 100 mM Tris-HCl, pH 8, and 10 mM MgCl2. Both adenylate cyclase activity and [3H][8-lysine]vasopressin binding activity were recovered in a -26,000 X g supernatant of detergent-treated membranes. The yield of solubilized adenylate cyclase was nearly 100%. The soluble enzyme was no longer sensitive to antidiuretic hormone but was slightly activated by sodium fluoride. The affinity of the soluble receptor for [8-lysine]vasopresin was les than that of the membrane-bound receptor (mean apparent Km values, respectively 10(-7) M and 2 X 10(-8) M), however binding cooperativity was preserved. Hill coefficients were 1.42 for the soluble receptor and 1.50 for the membrane receptor. The soluble receptor discriminated as efficiently as did the membrane receptor between [8-lysine-a1vasopressin and oxytocin. The yield of spolubilized receptor was only 30% despite the fact that all binding activity had disappeared from the residual pellet of detergent-treated membranes. When the membranous receptors were occupied before solubilization and the latter was performed under conditions in which dissociation of the hormone-receptor comples is slow, i.e. at low temperature, 65% to 100% of the hormone-receptor complex was recovered in the soluble fraction. The soluble hormone-receptor complex partially dissociated on rewarming whereas the free hormone concentration was kept unchanged in the medium. The residual binding capacity, which was 30% of the initial value, was identical with that determined when the receptor was solubilized in free form before incubation with labeled hormone. It was concluded that (a) solubilization of the receptor molecules was complete, (b) during solubilization two forms of the receptor appear, of which only one is accessible to the hormone, (c) occupancy of the receptor by the hormone prevented the formation of the nonaccessible form, and (d) some component or components of the soluble fraction might be responsible for the loss in apparent affinity.
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PMID:Solubilization of the [8-lysine]vasopressin receptor and adenylate cyclase from pig kidney plasma membranes. 17 Feb 74

Vasopressin-sensitive pig kidney adenylate cyclase is sensitive to several effectors, such as Mg2+, other divalent cations, and guanyl nucleotides. The purpose of the present study was to compare the main characteristics of adenylate cyclase activation by vasopressin, Mg2+, and GMPPNP, respectively. Mg2+ ions were shown to exert at least three different effects on adenylate cyclase. The substrate of the adenylate cyclase reaction is the Mg-ATP complex. Mg2+ interacts with an enzyme regulatory site. Finally, Mg2+ can modulate the hormonal response, with Mg2+ ions affecting the coupling function--that is, the quantitative relationship between receptor occupancy and adenylate cyclase activation. At all the magnesium concentrations tested, from 0.25 mM to 16 mM, adenylate cyclase activation was not a direct function of receptor occupancy. At low Mg2+ concentrations, adenylate cyclase activation dose-response curve to the hormone tended to be superimposable to the hormone dose-binding curve. These results suggest a role of magnesium at the coupling step between the hormone-receptor complex and adenylate cyclase response. Cobalt, but not calcium, ions could exert the same effects as Mg2+ ions on this coupling step. GMPPNP induced considerable adenylate cyclase activation (15 to 35 times the basal value). Activation by GMPPNP was highly time and temperature dependent. At 30 degrees C, a 20 to 60 min preincubation period in the presence of GMPPNP was needed to obtain maximal activation. The higher the dose of GMPPNP in the medium, the longer it took to reach equilibrium. At 15 degrees C, activation was still increasing with time after 3 hr preincubation in the presence of the nucleotide. GMPPNP was active in a 10(-8)M to 10(-5)M concentration range. Unlike the results obtained with lysine vasopressin, the kinetic characteristics of dose-dependent adenylate cyclase activation curves by GMPPNP were unaffected by varying Mg2+ concentrations except for the increase in velocity when raising Mg2+ concentration. It was not clear whether or not the activation processes by the hormone and by GMPPNP had common mechanisms.
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PMID:Vasopressin-sensitive kidney adenylate cyclase: modulation of the hormonal response. 17 20

An ADP-ribosyltransferase was purified approximately 500-fold from the supernatant fraction of turkey erythrocytes. The enzyme hydrolyzed [carbonyl-(14)C]NAD to ADP-ribose and [carbonyl-(14)C]nicotinamide at a low rate. Nicotinamide formation from NAD was enhanced by arginine methyl ester > D-arginine approximately L-arginine > guanidine; lysine, histidine, and citrulline were ineffective. Incubation of [adenine-U-(14)C]NAD and arginine methyl ester or arginine with the purified enzyme resulted in the formation of new compounds that contained (14)C, reacted with ninhydrin, and quenched background fluorescence of thin-layer plates viewed in ultraviolet light. Their mobilities on thin-layer chromatograms were indistinguishable from those of ADP-ribosylarginine methyl ester and ADP-ribosylarginine formed during incubation of choleragen with NAD and arginine methyl ester or arginine, respectively [Moss, J. & Vaughan, M. (1977) J. Biol. Chem. 252, 2455-2457]. The purified transferase also catalyzed the incorporation of label from [adenine-(14)C]-NAD into lysozyme, histones and polyarginine. When the (14)C-labeled lysozyme was incubated with snake venom phosphodiesterase, the radioactivity was released and, on thin-layer chromatograms, exhibited a mobility indistinguishable from that of 5'-AMP, as would be expected of an ADP-ribosylated protein, but not of a poly(ADP-ribosylated) product. The purified transferase activated rat brain adenylate cyclase and, as is the case with choleragen, activation was absolutely dependent on NAD. The presence in the avian erythrocyte of a protein that, like choleragen and Escherichia coli heat-labile enterotoxin, apparently activates adenylate cyclase and possesses ADP-ribosyl transferase activity is consistent with the view that the mechanisms through which the bacterial toxins produce pathology are not entirely foreign to vertebrate cells, at least some of which may possess and employ an analogous mechanism for activation of adenylate cyclase.
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PMID:Isolation of an avian erythrocyte protein possessing ADP-ribosyltransferase activity and capable of activating adenylate cyclase. 21 2

A comparative study was made of the stimulation of rat ovary adenyl cyclase by ovine luteinizing hormone (LH) and its methylated drrivative (obtained by reductive alkylation of the lysine residues). The apparent Km (half maximal activity) of native LH and methylated LH was similar but the maximal activity obtained with the methylated derivative was significantly higher (1.2-1.8 times). When EDTA was added to the incubation medium the maximal activity obtained with the methylated LH diminished and became even lower than that obtained with native LH.
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PMID:[Stimulation of rat ovarian adenyl cyclase by methylated luteinizing hormone (LH). The effect of ethylenediaminetetraacetic acid]. 81 54

Fresh frozen bovine parathyroid glands were defatted in acetone, when extracted with phenol. Following trichloroacetic acid precipitation, the resultant peptides were chromatographed on Sephadex G-100. Parathyroid hormone (BPTH) characteristically elutes in the fourth peak. However, we also observed significant hormonal activity, both biological and immunological, in the fifth elution peak. The peak V material had potent hypercalcemic activity in the rat and chick, and stimulated adenylate cyclase activity in the rat renal cortex bioassay. This material was further purified by ion exchange chromatography on carboxymethylcellulose in 8 M urea. The biological activity of the purified peptide (3700 MRC units/mg) was equivalent to that of the native hormone on a molar basis. Amino acid analysis, carboxypeptidase digestion, and partial Edman sequence analysis identified this material as BPTH 1-65, a hormonal fragment lacking the C-terminal 19 residues of the 84 residue hormone molecule. Several immunoassays using different anti-PTH antisera had variable reactivity toward the BPTH 1-65 fragment, showing that it may be useful for further characterizing antibody recognition sites. The presence of a lysine residue at position 65 suggests a tryptic-like cleavage may be responsible for the genesis of this hormonal fragment. Further investigation will be necessary to determine if this peptide has physiological significance.
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PMID:A biologically active hormonal fragment isolated from bovine parathyroid glands (BPTH 1-65). 114 77

Lysine vasopressin did not increase plasma FFAs level in man and in rat Pitressin and lysine vasopressin did not influence adenyl cyclase activity in rat epididymal fat pad, while ornithine vasopressin induced a statistically significant adenyl cyclase increment. These findings suggest that the adipokinetic acticity of ADH which has been correlated only with the amino acid arginine is also correlated with ornithine.
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PMID:Antidiuretic hormone and lipolysis. 114 94

Two series of neurohypophysial peptide amino-acylated derivatives were tested for their ability to activate plasma membrane adenylate cyclase prepared from pig or rat kidney. They were firstly [8-lysine]-vasopressin-related derivatives (Na-[Glycyl-Cys]1-[8-Lysine]-vasopressin and Na-[Glycyl-Glycyl-Cys51-[8-Lysine]-vasopressin) and secondly oxytocin-related derivatives (Na-[Glycyl-Cys-a1)-oxytocin, Na-[Leucyl-Glycyl-Glycyl--Cys]-oxytocin, and Na-[Glycyl-Cys]-[2-0methyl tyrosine]-oxtocin). The maximal adenylate cyclase activation induced by these peptides was lower than that induced by their respective parent hormones. After incubation of these analogues with plasma membranes obtained from the renal medulla, no significant release of parent hormones occurred. Good qualitative correlations were observed between relative antidiuretic activities measured in vivo and relative potencies in activating adenylate cyclase. It was concluded that direct action of peptides tested on the kidney is at least partly responsible for their antidiuretic activity in vivo.
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PMID:Renal adenylate cyclase activation by amino acylated vasopressin and oxytocin. 114 16

Polycations, including ribonuclease A, ribonuclease S protein and peptide, spermine, spermidine, and polylysines, enhance unstimulated and stimulated adenylate cyclase activity of beef thyroid membranes at low concentrations and inhibit these activities at high concentrations. Peak polylysine stimulation occurs with degrees of polymerization of 6 to 14, and for large polymers a potency limit for this maximum is reached at 4 X 10(-5) M expressed as lysine residues. Both enhancement and inhibition appear to be due to charge-charge interactions and are abolished by KC1. Polyanions are inhibitory only. The biphasic effect of polycations is seen on basal cyclase activity, occurs with prostaglandin E1- and 5'-guanylyl-imidodiphosphate-stimulated cyclase, but is most striking with thyrotropin. There is little enhancement of F--activated cyclase. The enhancement is not sensitive to changes in pH, Mg2+, or regenerating system and does not correlate with the stability constants between polycations and ATP. We suggest that the polycation effect is a general, electrostatic effect on membrane conformation and is not restricted to a particular receptor domain.
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PMID:Charge effects in the activation of adenylate cyclase. 115 87

The complete amino acid sequence was determined for bovine ubiquitin, and adenylate cyclase stimulating polypeptide, which is probably represented universally in living cells. Ubiquitin has a molecular weight of 8451 and consists of a single polypeptide chain containing 74 amino acid residues. It contains four arginine residues but no cysteine or trytophan residues. The first 61 amino acid residues were obtained by automated Edman degradations. Tryptic digestion of maleated ubiquitin yielded four peptide fragments that were resolved by molecular sieve chromatography and coded in order of decreasing chain length (MT-1, MT-2, MT-3, and MT-4). The automated sequenator determinations on native ubiquintin provided overlapping sequence data for three of these fragments that gave an order of MT-1, MT-3, and then MT-2; Peptide MT-4, a dipeptide, was therefore assigned to the C terminus, and the placement of peptide MT-2 was corroborated by analysis of data from carboxypeptidase digestions of maleated ubiquitin. Peptide MT-2 was domaleated and sequenced by manual Edman degradations through a single lysine residue. It was cleaved at this residue with trypsin, and the two resultant peptides were separated by ion-exchange chromatography. Manual sequencing of the C-terminal demaleated tryptic peptide of MT-2 completed the sequence of MT-2 and that of native ubiquitin. The sequence of ubiquitin was further confirmed and supported by amino acid and parital sequence anlysis of fragments obtained by digestion of maleated ubiquitin with chymotrypsin or staphylococcal protease.
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PMID:The complete amino acid sequence of ubiquitin, an adenylate cyclase stimulating polypeptide probably universal in living cells. 117 Aug 80


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