Faculty Opinions recommendation of Cyclic CMP and cyclic UMP mediate bacterial immunity against phages.

Hydrolysis of phosphatidylcholine by phospholipase A2 of synaptic membranes i n Tris-CHl buffer was stimulated by cyclic AMP, cyclic GMP, cyclic CMP, cyclic UMP and adenosine (0.1 mm). In the presence of 1 mm-NaF and cofactors, the same cyclic nucleotides and adenosine (10 mm) stimulated the incorporation of added oleate into the choline glycerophospholipids of synaptic membranes. Cyclic AMP and noradrenaline stimulated the incorporation of added oleate into position 2 of choline glycerophospholipid. Stimulation of net acylation was increased by preincubation in conditions which stimulated hydrolysis of phosphatidylcholine. Cyclic AMP only slightly stimulated the transfer of oleate from oleoyl-CoA into choline glycerophospholipid. The optimum concentration of CaCl2 for the stimulation of hydrolysis by phospholipase A2 by cyclic AMP was 1 mum. Stimulation of the incorporation of added oleate was maximal in the CaCl2 concentration range 1 mum-1mm. MgCl2 also enhanced stimulations, maximum effects being obtained with concentrations of 10 mum and 0.5 mm for hydrolysis by phospholipase A2 and incorporation of added oleate respectively. ATP enhanced the stimulation of incorporation of oleate but had no effect on the cyclic nucleotide stimulation of hydrolysis of added phosphatidylcholine by phospholipase A2. Adenosine, guanosine, ADP and 5′-AMP (all at 1 mm) inhibited the stimulation of incorporation of oleate by cyclic nucleotides and inhibited the transfer of oleate from oleoyl-CoA to phospholipid. They did not inhibit the stimulation of hydrolysis of added phosphatidylcholine (by phospholipase A2) by cyclic nucleotides, but inhibited the stimulation by noradrenaline, acetylcholine, 5-hydroxytryptamine, dopamine (3,4-dihydroxyphenethylamine) and histamine. Preincubation of synaptic membranes in the water or buffer increased the net activity of phospholipase A2. Preincubation with a mixture of ATP and MgCl2 increased the initial rate of acylation of membrane lipid.

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Decreased activity of cytidine 3′:5′-monophosphate (cyclic CMP) phosphodiesterase in the fast-growing Morris hepatoma 3924A, but not in the slow-growing Morris hepatoma 9618A

Biochemical and Biophysical Research Communications ◽

10.1016/0006-291x(78)91514-0 ◽

1978 ◽

Vol 83 (3) ◽

pp. 1140-1146 ◽

Cited By ~ 16

Author(s):

Mamoru Shoji ◽

Nancy L. Brackett ◽

David M. Helfman ◽

Harolf P. Morris ◽

J.F. Kuo

Keyword(s):

Fast Growing ◽

Morris Hepatoma ◽

Slow Growing ◽

Cyclic Cmp

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Radioimmunoassay of Cyclic AMP, Cyclic GMP, Cyclic CMP

Ions–Cyclic Nucleotides–Cholinergy ◽

10.1016/b978-0-08-023193-8.50023-0 ◽

1979 ◽

pp. 193-205

Author(s):

M.A. Delaage ◽

D. Roux ◽

H.L. Cailla

Keyword(s):

Cyclic Amp ◽

Cyclic Gmp ◽

Cyclic Cmp

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CYCLIC CMP PHOSPHODIESTERASE ACTIVATOR: INVOLVEMENT IN A HEREDITARY RETINAL DEGENERATION

Neurochemistry of the Retina ◽

10.1016/b978-0-08-025485-2.50036-5 ◽

1980 ◽

pp. 441-458

Author(s):

G. Chader ◽

Y. Liu ◽

P. O'Brien ◽

R. Fletcher ◽

G. Krishna ◽

...

Keyword(s):

Retinal Degeneration ◽

Hereditary Retinal Degeneration ◽

Cyclic Cmp

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Roles of Cyclic Nucleotides in the Inhibition of Platelet Function by Physiolocic and Pharmacological Agents

10.1055/s-0039-1684475 ◽

1979 ◽

Author(s):

R.J. Haslam

Keyword(s):

Platelet Aggregation ◽

Cyclic Amp ◽

Adenylate Cyclase ◽

Platelet Function ◽

Inhibitory Effects ◽

Pharmacological Agents ◽

Arterial Blood ◽

Cyclic Cmp ◽

Amp Inhibition

Cyclic AMP mediates the inhibitions of platelet aggregation caused by PCI2, PGE1 and PGD2. Thus, these compounds activate platelet adenylate cyclase and Increase platelet cyclic AMP; their inhibitory effects are blockod by inhibitor? of adenylate cyclase, are potentiated by inhibitors of cyclic AKP phosphodiesterase and are mimicked hy N6 ,2'-0-dibutyryl cyclic AMP. Inhibition of adenylate cyclase does not potentiate platelet aggregation in the absence of inhibitory prostaglandins, indicating that platelet cyclic AMP is too low to affect aggregation under these conditions. To determine whether platelets in the circulation are exposed to agents that increase platelet cyclic AMP, washed rabbi platelets labelled with [3H] adenine were incubated with rabbit arterial blood under various conditions; any increases in cyclic [3H]AMP were measured. These experiments showed that freshly taken rabbit arterial blood does not normally contain any factors that can increase platelet cyclic AMP sufficiently to affect platelet function; specifically, circulating PGI2 was less than 0.1 pmol/ml of blood. It follows that increases in cyclic AMP in circulating rabbit platelets must occur only locally or under special conditions. The role of the moderate increases in platelet cyclic CMP caused by aggregating agents remains uncertain, but the inhibition of aggregation by compounds such as sodium nitroprusside that increase cyclic CMP up to 100-fold suggests that cyclic CMP may, like cyclic AMP, be an inhibitory mediator.

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Cytidine 3',5'-monophosphate (cyclic CMP) formation in mammalian tissues

Science ◽

10.1126/science.22127 ◽

1977 ◽

Vol 198 (4321) ◽

pp. 1063-1065 ◽

Cited By ~ 39

Author(s):

S. Cech ◽

L. Ignarro

Keyword(s):

Mammalian Tissues ◽

Cyclic Cmp

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Further evidence for an allosteric model for ribonuclease

Biochemical Journal ◽

10.1042/bj1530329 ◽

1976 ◽

Vol 153 (2) ◽

pp. 329-337 ◽

Cited By ~ 16

Author(s):

E J Walker ◽

G B Ralston ◽

I G Darvey

Keyword(s):

Conformational Change ◽

Equilibrium Dialysis ◽

Kinetic Studies ◽

Experimental Systems ◽

Substrate Analogues ◽

Multiple Binding ◽

Rate Of Hydrolysis ◽

Hydrolysis Of ◽

Cyclic Cmp ◽

Allosteric Model

Evidence is presented from three experimental systems to support the allosteric model of Walker et al. (1975) (Biochem. J. 147, 425-433) which explains the substrate-concentration-dependent transition observed in the RNAase (ribonuclease)-catalysed hydrolysis of 2‘:3’-cyclic CMP (cytidine 2‘:3’-cyclic monophosphate). 1. Kinetic studies of the initial rate of hydrolysis of 2‘:3’-cyclic CMP show that the midpoint of the transition shifts to lower concentrations of 2‘:3’-cyclic CMP in the presence of the substrate analogues 3′-CMP, 5′-CMP, 3′-AMP, 3′-UMP and Pi; 2′-CMP and 2′-UMP do not cause such a shift. 2. Trypsin-digestion studies show that a conformational change in RNAase to a form less susceptible to tryptic inactivation is induced in the presence of the substrate analogues 3′-CMP, 5′-CMP, 3′-AMP, and 3′-UMP. 2′-CMP, 2′-AMP and 2′-UMP do not induce this conformational change. 3. Equilibrium-dialysis experiments demonstrate the multiple binding of molecules of 3′-CMP, 3′-AMP and 5′-AMP to a molecule of RNAase. 2′-CMP binds the ratio 1:1 over the analogue concentration range studied.

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