scholarly journals The dephosphorylation pathway of d-myo-inositol 1,3,4,5-tetrakisphosphate in rat brain

1987 ◽  
Vol 247 (3) ◽  
pp. 635-639 ◽  
Author(s):  
C Erneux ◽  
A Delvaux ◽  
C Moreau ◽  
J E Dumont
Keyword(s):  
Rat Brain ◽  
Soluble Fraction ◽  
Deae Cellulose ◽  
Phosphatase Activities ◽  
Inositol 1 ◽  
The Third ◽  
Inositol 1,4,5 Trisphosphate ◽  
Hydrolysis Of ◽  
Blue Sepharose

Dephosphorylation of inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P4] was measured in both the soluble and the particulate fractions of rat brain homogenates. Analysis of the hydrolysis of [4,5-32P]Ins(1,3,4,5)P4 showed that for both fractions the 5-phosphate of Ins(1,3,4,5)P4 was removed and inositol 1,3,4-trisphosphate [Ins(1,3,4)P3] was specifically produced. In the soluble fraction, Ins(1,3,4)P3 was further hydrolysed at the 1-phosphate position to inositol 3,4-bisphosphate[Ins(3,4)P2]. DEAE-cellulose chromatography of the soluble fraction separated the phosphatase activities into three peaks. The first hydrolysed both Ins(1,3,4,5)P4 and inositol 1,4,5-trisphosphate, the second inositol 1-phosphate and the third Ins(1,3,4)P3 and inositol 1,4-bisphosphate, [Ins(1,4)P2]. Further purification of the third peak on either Sephacryl S-200 or Blue Sepharose could not dissociate these two activities [i.e. with Ins(1,4)P2 and Ins(1,3,4)P3 as substrates]. The dephosphorylation of Ins(1,3,4)P3 could be inhibited by the addition of Li+.

scholarly journals Enzymic dephosphorylation of d-myo-inositol 1,4-bisphosphate in rat brain

1987 ◽  
Vol 242 (1) ◽  
pp. 193-198 ◽  
Author(s):  
A Delvaux ◽  
C Erneux ◽  
C Moreau ◽  
J E Dumont
Keyword(s):  
Rat Brain ◽  
Phosphatase Activity ◽  
Psychiatric Treatment ◽  
Soluble Fraction ◽  
Deae Cellulose ◽  
Brain Homogenate ◽  
Lithium Salts ◽  
Phosphatase Activities ◽  
Assay Mixture ◽  
Inositol 1,4,5 Trisphosphate

Inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] and inositol 1,4-bisphosphate [Ins(1,4)P2] phosphatase activities were measured in both 180,000 g (60 min) particulate and supernatant fractions of rat brain homogenates. Although Ins(1,4,5)P3 was mostly hydrolysed by a particulate phosphatase [Erneux, Delvaux, Moreau & Dumont (1986) Biochem. Biophys. Res. Commun. 134, 351-358], Ins(1,4)P2 phosphatase was predominantly soluble. The latter enzyme was Mg2+-dependent and sensitive to thiol-blocking agents (e.g. p-hydroxymercuribenzoate). In contrast with Ins(1,4,5)P3 phosphatase activity measured in the soluble fraction, Ins(1,4)P2 phosphatase was insensitive to 0.001-1 mM-2,3-bisphosphoglycerate. Lithium salts, widely used in psychiatric treatment, inhibited both Ins(1,4)P2 and Ins(1)P1 phosphatase activities of the crude soluble fraction. In particular, 50% inhibition of phosphatase activity, with 2 microM-Ins(1,4)P2 as substrate, was achieved at 3-5 mM-LiCl. At these concentrations, LiCl did not change Ins(1,4,5)P3 phosphatase activity measured in the same fraction with 1-4 microM-Ins(1,4,5)P3 as substrate. Chromatography of the soluble fraction of a rat brain homogenate on DEAE-cellulose resolved three phosphatase activities. These forms, peaks I, II and III, dephosphorylated Ins(1,4,5)P3, Ins(1)P1 and Ins(1,4)P2 respectively. If LiCl (10 mM) was included in the assay mixture, it inhibited both peak-II Ins(1)P1 phosphatase and peak-III Ins(1,4)P2 phosphatase, suggesting the existence of at least two Li+-sensitive phosphatases.

scholarly journals Substrate specificity and other properties of the inducible S3 secondary alkylsulphohydrolase purified from the detergent-degrading bacterium Pseudomonas C12B

1980 ◽  
Vol 187 (1) ◽  
pp. 181-190 ◽  
Author(s):  
D J Shaw ◽  
K S Dodgson ◽  
G F White
Keyword(s):  
Carbon Atom ◽  
Deae Cellulose ◽  
Maximum Activity ◽  
Sulphate Group ◽  
Alkyl Chains ◽  
Degrading Bacterium ◽  
Ester Linkage ◽  
Hydrolysis Of ◽  
Blue Sepharose ◽  
Asymmetric Carbon

The inducible S3 secondary alkylsulphohydrolase of the soil bacterium Pseudomonas C12B was purified to homogeneity (683-fold from cell-free extracts by a combination of column chromatography on DEAE-cellulose. Sephadex G-100 and Blue Sepharose CL-6B. The enzyme has a molecular weight in the region of 40000–46000, and is active over a broad range of pH from 5 to 9, with maximum activity at pH 8.2. The preferred substrates of the enzyme are the symmetrical secondary alkylsulphate esters such as heptan-4-yl sulphate and nonan-5-yl sulphate and the asymmetric secondary octyl and nonyl sulphate esters with the sulphate group attached to C-3 or C-4. However, for each asymmetric ester, the L-isomer is much more readily hydrolysed than the D-isomer. This specificity is interpreted in terms of a three-point attachment of the substrate to the enzyme's active site. The alkyl chains on either side of the esterified carbon atom are bound in two separate sites, one of which can only accommodate alkyl chains of limited size. The third site binds the sulphate group. Enzymic hydrolysis of this group is accompanied by complete inversion of configuration at the asymmetric carbon atom. The implied cleavage of the C–O bond of the C–O–S ester linkage was confirmed by 18O-incorporation studies.

scholarly journals The Mood Stabilizer Valproate Inhibits both Inositol- and Diacylglycerol-signaling Pathways in Caenorhabditis elegans

2008 ◽  
Vol 19 (5) ◽  
pp. 2241-2250 ◽  
Author(s):  
Suzumi M. Tokuoka ◽  
Adolfo Saiardi ◽  
Stephen J. Nurrish
Keyword(s):  
Bipolar Disorder ◽  
Caenorhabditis Elegans ◽  
Phorbol Ester ◽  
Acetylcholine Release ◽  
Inositol Phosphate ◽  
Mood Stabilizer ◽  
Egg Laying ◽  
Inositol 1 ◽  
Inositol 1,4,5 Trisphosphate ◽  
Hydrolysis Of

The antiepileptic valproate (VPA) is widely used in the treatment of bipolar disorder, although the mechanism of its action in the disorder is unclear. We show here that VPA inhibits both inositol phosphate and diacylglycerol (DAG) signaling in Caenorhabditis elegans. VPA disrupts two behaviors regulated by the inositol-1,4,5-trisphosphate (IP3): defecation and ovulation. VPA also inhibits two activities regulated by DAG signaling: acetylcholine release and egg laying. The effects of VPA on DAG signaling are relieved by phorbol ester, a DAG analogue, suggesting that VPA acts to inhibit DAG production. VPA reduces levels of DAG and inositol-1-phosphate, but phosphatidylinositol-4,5-bisphosphate (PIP2) is slightly increased, suggesting that phospholipase C-mediated hydrolysis of PIP2 to form DAG and IP3 is defective in the presence of VPA.

scholarly journals Changes in the levels of inositol phosphates after agonist-dependent hydrolysis of membrane phosphoinositides

1983 ◽  
Vol 212 (2) ◽  
pp. 473-482 ◽  
Author(s):  
M J Berridge ◽  
R M C Dawson ◽  
C P Downes ◽  
J P Heslop ◽  
R F Irvine
Keyword(s):  
Salivary Gland ◽  
Parotid Gland ◽  
Anion Exchange ◽  
Inositol Phosphates ◽  
Brain Slices ◽  
Exchange Chromatography ◽  
Inositol 1 ◽  
Inositol 1,4,5 Trisphosphate ◽  
Cyclic Phosphate ◽  
Hydrolysis Of

The formation of inositol phosphates in response to agonists was studied in brain slices, parotid gland fragments and in the insect salivary gland. The tissues were first incubated with [3H]inositol, which was incorporated into the phosphoinositides. All the tissues were found to contain glycerophosphoinositol, inositol 1-phosphate, inositol 1,4-bisphosphate and inositol 1,4,5-trisphosphate, which were identified by using anion-exchange and high-resolution anion-exchange chromatography, high-voltage paper ionophoresis and paper chromatography. There was no evidence for the existence of inositol 1:2-cyclic phosphate. A simple anion-exchange chromatographic method was developed for separating these inositol phosphates for quantitative analysis. Stimulation caused no change in the levels of glycerophosphoinositol in any of the tissues. The most prominent change concerned inositol 1,4-bisphosphate, which increased enormously in the insect salivary gland and parotid gland after stimulation with 5-hydroxytryptamine and carbachol respectively. Carbachol also induced a large increase in the level of inositol 1,4,5-trisphosphate in the parotid. Stimulation of brain slices with carbachol induced modest increase in the bis- and tris-phosphate. In all the tissues studied, there was a significant agonist-dependent increase in the level of inositol 1-phosphate. The latter may be derived from inositol 1,4-bisphosphate, because homogenates of the insect salivary gland contain a bisphosphatase in addition to a trisphosphatase. These results suggest that the earliest event in the stimulus-response pathway is the hydrolysis of polyphosphoinositides by a phosphodiesterase to yield inositol 1,4,5-trisphosphate and inositol 1,4-bisphosphate, which are subsequently hydrolysed to inositol 1-phosphate and inositol. The absence of inositol 1:2-cyclic phosphate could indicate that, at very short times after stimulation, phosphatidylinositol is not catabolized by its specific phosphodiesterase, or that any cyclic derivative liberated is rapidly hydrolysed by inositol 1:2-cyclic phosphate 2-phosphohydrolase.

Regulation and Partly Purification of the ATP-Sulfurylase from the Cyanobacterium Synechococcus 6301

1992 ◽  
Vol 47 (1-2) ◽  
pp. 95-101 ◽  
Author(s):  
Divya Mishra ◽  
Ahlert Schmidt
Keyword(s):  
Batch Culture ◽  
Specific Activity ◽  
Deae Cellulose ◽  
Fold Increase ◽  
Resting Cells ◽  
Atp Sulfurylase ◽  
The Third ◽  
Synechococcus 6301 ◽  
Blue Sepharose

Abstract ATP-sulfurylase from the cyanobacterium Synechococcus 6301 was regulated in vivo during growth in batch culture. The activity was highest at the third day after inoculation, declining afterwards to a level found in resting cells. During growth with air supplemented with 2% CO2 this activity increased 3-fold compared to controls grown with normal air as CO2 source. Addition of either nitrite or urea enhanced ATP-sulfurylase activity about 2-fold, whereas cysteine and especially methionine decreased ATP-sulfurylase activity to 5% of controls without treatment. The ATP-sulfurylase was purified by conventional techniques using DEAE-cellulose chromatography and further separation on blue sepharose achieving a 250-fold increase in the specific activity. An apparent Kᴍ of 5 μᴍ for APS and of 40 μᴍ for pyrophosphate was determined with the purified enzyme fraction.

scholarly journals Evidence that inositol 1-phosphate in brain of lithium-treated rats results mainly from phosphatidylinositol metabolism

1987 ◽  
Vol 242 (2) ◽  
pp. 517-524 ◽  
Author(s):  
K E Ackermann ◽  
B G Gish ◽  
M P Honchar ◽  
W R Sherman
Keyword(s):  
Rat Brain ◽  
High Speed ◽  
Inositol Phosphate ◽  
Bovine Brain ◽  
Lower Sensitivity ◽  
Inositol 1 ◽  
Rate Of Hydrolysis ◽  
Tissue Contents ◽  
Hydrolysis Of

In cerebral cortex of rats treated with increasing doses of LiCl, the relative concentrations of Ins(1)P, Ins(4)P and Ins(5)P (when InsP is a myo-inositol phosphate) are approx. 10:1:0.2 at all doses. In rats treated with LiCl followed by increasing doses of pilocarpine a similar relationship occurs. myo-Inositol-1-phosphatase (InsP1ase) from bovine brain hydrolyses Ins(1)P, Ins(4)P and Ins(5)P at comparable rates, and these substrates have similar Km values. The hydrolysis of Ins(4)P is inhibited by Li+ to a greater degree than is hydrolysis of Ins(1)P and Ins(5)P. D-Ins(1,4,5)P3 and D-Ins(1,4)P2 are neither substrates nor inhibitors of InsP1ase. A dialysed high-speed supernatant of rat brain showed a greater rate of hydrolysis of Ins(1)P than of D-Ins(1,4)P2 and a lower sensitivity of the bisphosphate hydrolysis to LiCl, as compared with the monophosphate. That enzyme preparation produced Ins(4)P at a greater rate than Ins(1)P when D-Ins(1,4)P2 was the substrate. The amount of D-Ins(3)P [i.e. L-Ins(1)P, possibly from D-Ins(1,3,4)P3] is only 11% of that of D-Ins(1)P on stimulation with pilocarpine in the presence of Li+. DL-Ins(1,4)P2 was hydrolysed by InsP1ase to the extent of about 50%; both Ins(4)P and Ins(1)P are products, the former being produced more rapidly than the latter; apparently L-Ins(1,4)P2 is a substrate for InsP1ase. Li+, but not Ins(2)P, inhibited the hydrolysis of L-Ins(1,4)P2. The following were neither substrates nor inhibitors of InsP1ase; Ins(1,6)P2, Ins(1,2)P2, Ins(1,2,5,6)P4, Ins(1,2,4,5,6)P5, Ins(1,3,4,5,6)P5 and phytic acid. myo-Inositol 1,2-cyclic phosphate was neither substrate nor inhibitor of InsP1ase. We conclude that the 10-fold greater tissue contents of Ins(1)P relative to Ins(4)P in both stimulated and non-stimulated rat brain in vivo are the consequence of a much larger amount of PtdIns metabolism than polyphosphoinositide metabolism under these conditions.

scholarly journals Synthetic inositol 1,3,4,5-tetrakisphosphate analogues

1991 ◽  
Vol 276 (2) ◽  
pp. 333-336 ◽  
Author(s):  
M Hirata ◽  
Y Kimura ◽  
T Ishimatsu ◽  
F Yanaga ◽  
T Shuto ◽  
...  
Keyword(s):  
Active Sites ◽  
Erythrocyte Ghosts ◽  
Phosphatase Activities ◽  
Inositol 1,4,5 Trisphosphate ◽  
Hydrolysis Of

Inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P4] analogues were synthesized and their effects on [3H]Ins(1,3,4,5)P4 5-phosphatase, [3H]Ins(1,3,4,5)P4 3-phosphatase and [3H]inositol 1,4,5-trisphosphate [3H]Ins(1,4,5)P3] 5-phosphatase activities were examined. The Ins(1,3,4,5)P4 analogue with the aminobenzoyl group at the 2-position of Ins(1,3,4,5)P4 inhibited the hydrolysis of 5-phosphate of [3H]Ins(1,3,4,5)P4 catalysed by erythrocyte ghosts, with a lower Ki value than seen with Ins(1,3,4,5)P4, whereas the analogue with the aminocyclohexanecarbonyl group at the same position had a higher Ki value. The Ins(1,4,5)P3 analogues that we had previously synthesized were also capable of inhibiting this process, with the same tendency as Ins(1,3,4,5)P4 analogues. Such differences in the potency among Ins(1,3,4,5)P4 and Ins(1,4,5)P3 analogues were applicable to other phosphatase activities, namely [3H]Ins(1,3,4,5)P4 3-phosphatase and [3H]Ins(1,4,5)P3 5-phosphatase. These results suggest that the active sites of these enzymes may catalyse the dephosphorylation in a similar fashion.

scholarly journals Rat brain inositol 1,4,5-trisphosphate 3-kinase. Ca2+-sensitivity, purification and antibody production

1990 ◽  
Vol 268 (1) ◽  
pp. 213-217 ◽  
Author(s):  
K Takazawa ◽  
M Lemos ◽  
A Delvaux ◽  
C Lejeune ◽  
J E Dumont ◽  
...  
Keyword(s):  
Western Blot ◽  
Human Brain ◽  
Affinity Chromatography ◽  
Rat Brain ◽  
Antibody Production ◽  
Kinase Activity ◽  
Bovine Brain ◽  
Sds Page ◽  
Inositol 1,4,5 Trisphosphate ◽  
Blue Sepharose

Inositol 1,4,5-trisphosphate (InsP3) 3-kinase catalyses the ATP-dependent phosphorylation of InsP3 to inositol 1,3,4,5-tetrakisphosphate (InsP4). InsP3 3-kinase was purified from rat brain by Blue-Sepharose, phosphocellulose and calmodulin (CaM)-Sepharose affinity chromatography. The purified enzyme was stimulated by Ca2+/CaM by 3-6-fold as compared with the activity measured in the presence of EGTA. Rat brain InsP3 3-kinase activity was associated with two silver-stained bands of about equal activity which migrated with an apparent Mr of 50,000 on SDS/polyacrylamide gels. InsP3 3-kinase activity from rat brain could be immunoprecipitated by an antiserum against the SDS/PAGE-purified 50,000-Mr protein doublet. InsP3 kinase activity from bovine brain and the InsP3 5-phosphatase activity from rat brain were not immunoprecipitated. On Western blot, the human brain crude InsP3 3-kinase reacted specifically, but less strongly than the rat brain enzyme, with the antiserum.

scholarly journals The dephosphorylation of inositol 1,4-bisphosphate to inositol in liver and brain involves two distinct Li+-sensitive enzymes and proceeds via inositol 4-phosphate

1988 ◽  
Vol 249 (1) ◽  
pp. 143-148 ◽  
Author(s):  
C I Ragan ◽  
K J Watling ◽  
N S Gee ◽  
S Aspley ◽  
R G Jackson ◽  
...  
Keyword(s):  
Phosphatase Activity ◽  
Soluble Fraction ◽  
Inositol 1 ◽  
Hydrolysis Of

1. Hydrolysis of both enantiomers of inositol 1-phosphate and both enantiomers of inositol 4-phosphate to inositol is inhibited by LiCl in liver and brain. 2. The phosphatase activity is predominantly soluble. 3. Inositol 1,4-bisphosphate is also hydrolysed by the soluble fraction of liver and brain. 4. Bisphosphatase activity is inhibited by LiCl, but is less sensitive than monophosphatase activity. 5. The product of bisphosphatase in liver and brain is inositol 4-phosphate.

Ethanol and inositol 1,4,5-trisphosphate mobilize calcium from rat brain microsomes

Alcohol ◽  
1989 ◽  
Vol 6 (6) ◽  
pp. 431-436 ◽  
Author(s):  
Tina Machu ◽  
John J. Woodward ◽  
Steven W. Leslie
Keyword(s):  
Rat Brain ◽  
Inositol 1,4,5 Trisphosphate ◽  
Brain Microsomes
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