Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.6.1.1 (adenylate cyclase)
 19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
 ...
PMID:Isolation of an avian erythrocyte protein possessing ADP-ribosyltransferase activity and capable of activating adenylate cyclase. 21 2

Escherichia coli heat-labile enterotoxin (labile toxin, LT) catalyzed the hydrolysis of NAD to ADP-ribose and nicotinamide and the ADP-ribosylation of arginine (Moss, J., and Richardson, S.H. (1978) J. Clin. Invest. 62, 281-285). Analysis of the product of the ADP-ribosylation of arginine by nuclear magnetic resonance spectroscopy indicated that the reaction was stereospecific and resulted in the formation of alpha-ADP-ribosyl-L-arginine. This reaction product rapidly anomerized to yield a mixture of the alpha and beta forms. In the presence of [adenine-U-14C]NAD, E. coli enterotoxin catalyzed the transfer of the radiolabel to proteins; the ADP-ribosylation of proteins was inhibited by arginine methyl ester, an alternative substrate. Digestion of the 14C-protein with snake venom phosphodiesterase released predominantly 5'-AMP. No product was obtained with a mobility similar to that of 2'-(5''-phosphoribosyl)-5'-AMP. This result is consistent with the covalent attachment by the enterotoxin of ADP-ribose rather than poly(ADP-ribose) to protein. Thus, LT is catalytically equivalent to choleragen, an enterotoxin of Vibrio cholerae, and activates adenylate cyclase through a similar stereospecific ADP-ribosylation reaction.
 ...
PMID:NAD-dependent ADP-ribosylation of arginine and proteins by Escherichia coli heat-labile enterotoxin. 22 95

Rat liver plasma membranes are shown to catalyze the formation of adenosine 5'-phosphoroglycerol and adenosine 5'-phosphoromethanol from ATP and glycerol or methanol, respectively. In the presence of 2.7 M glycerol and 1 mM ATP, 30 nmol of adenosine 5'-phosphoroglycerol were formed in 10 min per mg of rat liver plasma membranes. The structures of these phosphodiesters were determined from the following evidence. Radioactivity was incorporated into the nucleotide from [alpha-32P]ATP, [2,8-3H]ATP, or [2-3H]glycerol. Treatment with snake venom phosphodiesterase I converted the nucleotides to AMP. The compound formed from glycerol and ATP co-migrated with adenosine 5'-phosphoroglycerol synthesized from glycerol and adenosine 5'-phosphoromorpholidate in five thin layer chromatography systems. The methyl derivative co-migrated with adenosine 5'-phosphoromethanol synthesized from methanol and adenosine 5'-phosphormorpholidate in several thin layer chromatography systems. The synthesis of these phosphodiesters was also catalyzed by chicken embryo fibroblast membranes and solubilized rat liver plasma membranes but not by rat heart plasma membrane preparations. Formation of significant amounts of these phosphodiesters required relatively high concentrations of the alcohols (greater than 1 M). The alcohol concentration dependence did not exhibit substrate saturation at physiologically meaningful concentrations of glycerol or methacol. It is proposed that either the alcohols examined were not the natural substrates for this enzyme or that the alcohol/AMP phosphodiesters were formed as a result of trapping of an enzyme/nucleotide intermediate. Adenosine 5'-phosphoroglycerol formation was inhibited approximately 50% by 15 mM NaF. Epinephrine, norepinephrine, glucagon, and prostaglandin E1 were without effect. Alloxan, an inhibitor of adenylate cyclase did not inhibit formation of adenosine 5'-phosphoroglycerol. It is concluded that adenylate cyclase was not responsible for formation of these phosphodiesters. The physiological significance of this reaction remains undefined.
 ...
PMID:Formation of adenosine 5'-phosphoroglycerol from ATP and glycerol by rat liver plasma membranes. 83 37

Gentamicin nucleotidyltransferase-catalyzed reaction of (Sp)-[alpha-17O]dATP with tobramycin produced 2"-(2'-deoxyadenosine 5'-[17O]phosphoryl)tobramycin. The configuration at phosphorus in this product was shown to be Rp by chemical degradation to chiral [17O, 18O]dAMP using a stereochemically defined procedure, and determination of the configuration at phosphorus in this product. Periodate-base treatment of 2"-(2'-deoxyadenosine 5'-[17O]phosphoryl)tobramycin followed by NaBH4 reduction produced (2-glyceryl)-[17O]dAMP, which upon snake venom phosphodiesterase-catalyzed hydrolysis in H(2)18O produced [17O,18O] dAMP. The configuration at phosphorus in this product was shown to be S by enzymatic phosphorylation to [17O,18O]dATP, adenylylcyclase (Bordetella pertussis)-catalyzed cyclization to 3',5'-cyclic [17O,18O]dAMP, and 31P NMR analysis of the ethyl esters. Since snake venom phosphodiesterase-catalyzed hydrolyses proceed with retention of configuration at phosphorus, (Sp)-[17O,18O]dAMP must have been produced from (Rp)-(2-glyceryl)-[17O]dAMP; and since the chemical degradation to the latter compound did not involve cleavage of any bonds to phosphorus, the initial enzymatic product must have been (Rp)-2"-(2'-deoxyadenosine 5'-[17O]phosphoryl)tobramycin. Therefore, nucleotidyl transfer catalyzed by gentamicin nucleotidyl-transferase proceeds with inversion of configuration at phosphorus, and the reaction mechanism involves an uneven number of phosphotransfer steps. Inasmuch as this is an uncomplicated two-substrate group transfer reaction, the mechanism probably involves direct nucleotidyl transfer from the nucleoside triphosphate to the aminoglycoside. The B. pertussis adenylylcyclase reaction was shown to proceed with inversion at phosphorus, as has been established for other adenylylcyclases.
 ...
PMID:Gentamicin nucleotidyltransferase. Stereochemical inversion at phosphorus in enzymatic 2'-deoxyadenylyl transfer to tobramycin. 287 83

Choleragen-dependent ADP ribosylation of soluble proteins from bovine thymus, using [32P]NAD as substrate, was increased 3- to 4-fold by GTP. The effect was specific for nucleoside triphosphate, with GTP approximately equal to ITP greater than CTP greater than ATP greater than UTP. Half-maximal enhancement was observed with 0.5 mM GTP. The magnitude of the GTP effect decreased with increasing NAD concentration; GTP had no effect on hydrolysis of NAD at low NAD concentrations. Digestion of ADP-ribosylated proteins with snake venom phosphodiesterase yielded primarily 5'-AMP. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of soluble proteins from thymus after incubation with choleragen and [32P]NAD separated numerous ADP-ribosylated proteins; radioactivity in all bands was increased by nucleoside triphosphate. Choleragen catalyzed the ADP ribosylation of several purified proteins; depending on the protein, GTP either increased, decreased, or had no effect on the extent of ADP ribosylation. Choleragen-dependent ADP ribosylation of a wide variety of proteins is consistent with the possibility that intoxication results in covalent modification of more than one cellular protein and perhaps alters the activity of other enzymes in addition to adenylate cyclase.
 ...
PMID:Effects of GTP on choleragen-catalyzed ADP ribosylation of membrane and soluble proteins. 624 10