scholarly journals A comparison of d-inositol 1:2-cyclic phosphate 2-phosphohydrolase with other phosphodiesterases of kidney

1973 ◽  
Vol 134 (1) ◽  
pp. 59-67 ◽  
Author(s):  
R. M. C. Dawson ◽  
N. G. Clarke
Keyword(s):  
Guinea Pig ◽  
Rat Kidney ◽  
Kidney Tissue ◽  
Outer Cortex ◽  
Inositol 1 ◽  
Brush Borders ◽  
Straight Portion ◽  
Membrane Bound ◽  
Cyclic Phosphate ◽  
Hydrolysis Of

1. The ability to hydrolyse various phosphodiesterase substrates was examined in subcellular fractions of rat kidney and in serial slices of the kidneys of mouse, rat, guinea pig and ox cut from the cortex perimeter inwards. 2. d-Inositol 1:2-cyclic phosphate 2-phosphohydrolase could be clearly distinguished from phosphodiesterases which hydrolyse 2′:3′- and 3′:5′-cyclic AMP and p-nitrophenyl thymidine 5′-phosphate (phosphodiesterase I). The hydrolysis of sn-glycero-3-phosphorylcholine showed a distribution identical with that of particle-bound d-inositol 1:2-cyclic phosphate 2-phosphodiesterase, but there was a 30-fold difference in the ratio of enzyme activities between the rat and guinea pig. 3. In rat and mouse kidney, d-inositol 1:2-cyclic phosphate 2-phosphohydrolase is virtually all membrane bound and in the outer cortex, whereas in guinea-pig kidney the enzyme is almost entirely soluble and located throughout the kidney tissue. Some properties of the soluble enzyme are described. 4. Distribution and histochemical studies indicated that in the rat and mouse, phosphodiesterase I is associated with the brush borders of the straight portion (pars recta) of the proximal tubule, whereas inositol 1:2-cyclic phosphate 2-phosphohydrolase and probably glycerylphosphorylcholine diesterase are associated with the brush borders of the convoluted part of the tubule (pars convoluta).

scholarly journals Localization of d-myoinositol 1:2-cyclic phosphate 2-phosphohydrolase in rat kidney

1972 ◽  
Vol 130 (1) ◽  
pp. 229-238 ◽  
Author(s):  
N. Clarke ◽  
R. M. C. Dawson
Keyword(s):  
Alkaline Phosphatase ◽  
Rat Kidney ◽  
Gradient Centrifugation ◽  
Subcellular Fractionation ◽  
Proximal Tubules ◽  
Outer Cortex ◽  
Inositol 1 ◽  
Brush Borders ◽  
Cyclic Phosphate ◽  
Pars Convoluta

1. On subcellular fractionation of rat kidney homogenates by differential and density-gradient centrifugation, the bulk of the inositol 1:2-cyclic phosphate 2-phosphohydrolase activity remains with the alkaline phosphatase activity, suggesting localization in the brush borders of the proximal tubules. 2. Histochemical studies with a medium containing inositol 1:2-cyclic phosphate and Escherichia coli phosphomonoesterase show Gomori staining around the brush borders of the proximal tubules in the outer cortex only. 3. Serial sections across the kidney from cortex perimeter to papilla suggest that the inositol 1:2-cyclic phosphate 2-phosphohydrolase has a limited distribution along the proximal tubule of the nephron, probably being limited to the pars convoluta, whereas the alkaline phosphatase extends along the pars recta.

scholarly journals A phosphodiesterase in rat kidney cortex that hydrolyses glycerylphosphorylinositol

1977 ◽  
Vol 162 (2) ◽  
pp. 241-245 ◽  
Author(s):  
R M C Dawson ◽  
N Hemington
Keyword(s):  
Rat Kidney ◽  
Kidney Cortex ◽  
Enzyme Complex ◽  
Alkaline Ph ◽  
Outer Cortex ◽  
Rat Kidney Cortex ◽  
Low Concentrations ◽  
Cyclic Phosphate

1. A phosphodiesterase, active at an alkaline pH, is present in the outer cortex of rat kidney and hydrolyses glycerylphosphorylinositol into glycerol and phosphorylinositol. Some inositol cyclic phosphate can also be formed indicating that the enzyme can act as a cyclizing phosphotransferase. 2. The enzyme is stimulated by Ca2+(2-3mM) whereas Mg2+ is inhibitory. 3. The activity is markedly stimulated by low concentrations of thiol reagents (1-2mM) such as cysteine or dithiothreitol. 4. The properties of the enzyme have been compared with glycerylphosphinicocholine diesterase (EC 3.1.4.2), which is also present in the isolated enzyme complex, and it is concluded that the enzymes have separate identities.

An ATP-inhibited soluble 5'-nucleotidase of rat kidney

1988 ◽  
Vol 254 (2) ◽  
pp. F191-F195
Author(s):  
M. Le Hir ◽  
U. C. Dubach
Keyword(s):  
High Speed ◽  
Catalytic Properties ◽  
Divalent Cations ◽  
Rat Kidney ◽  
Maximal Activity ◽  
Rate Of Hydrolysis ◽  
Membrane Bound ◽  
Ph Range ◽  
Hydrolysis Of

Hydrolysis of 5'-AMP by 5'-nucleotidase is a possible source of adenosine in the kidney. A renal membrane-bound ecto-5'-nucleotidase has been previously described. The present study deals with the catalytic properties of a 5'-AMP phosphohydrolase partially purified from high-speed supernatants of rat kidney homogenates. It exhibits phosphatase activity toward 5'-AMP, 5'-IMP, and 5'-GMP, but not toward 2'- and 3'-AMP and corresponds therefore to a 5'-nucleotidase. The hydrolysis of 5'-AMP by the soluble 5'-nucleotidase requires divalent cations. Maximal activity is reached with 10 microM of either Mn2+ or Co2+, whereas half-maximal activity is obtained with approximately 400 microM Mg2+. The soluble 5'-nucleotidase exhibits Michaelis-Menten kinetics with a Km of 9.5 microM for 5'-AMP. In the presence of 1 mM of free Mg2+, physiological concentrations of ATP provoke an increase of the Km for 5'-AMP and a decrease of Vmax. An increase of the pH of 0.4 units in the pH range 6.4-7.4 roughly doubles the rate of hydrolysis of 5'-AMP. The effects of ATP and of the pH are compatible with a role of the renal soluble 5'-nucleotidase in the hydrolysis of 5'-AMP and in the production of adenosine during hypoxia.

The Hydrolysis of Glycine Oligopeptides by Guinea-Pig Intestinal Mucosa and by Isolated Brush Borders

1973 ◽  
Vol 45 (6) ◽  
pp. 803-816
Author(s):  
T. J. Peters
Keyword(s):  
Guinea Pig ◽  
Intestinal Mucosa ◽  
Brush Border ◽  
Enzyme Reaction ◽  
Intestinal Lumen ◽  
Small Intestinal Mucosa ◽  
Peptidase Activity ◽  
Reaction Products ◽  
Brush Borders ◽  
Hydrolysis Of

1. The relative rates of hydrolysis of a series of glycine homopeptides by guinea-pig small intestinal mucosa and by isolated brush borders have been studied. Oligopeptides up to and including hexaglycine were hydrolysed. No activity was detected against a series of homopolypeptides of molecular weight 10000–100000. 2. Except for activity against diglycine, the peptidase activity was greater in the brush-border fraction than in the original homogenate. The relative activity of the peptidase in the brush borders compared to the homogenate increased with increasing length oligopeptide substrate. 3. Analysis of the enzyme reaction products indicated that the brush border contained an exopeptidase. Studies with peptide derivatives containing N- and C-terminal blocking groups and with tetraglycine synthesized with either the N- or C-terminal residues labelled, demonstrated that the brush borders contained an amino-oligopeptidase. 4. Studies with inhibitors and with purified gastric and pancreatic enzymes indicated that this glycine oligopeptidase activity was not due to enzymes from the intestinal lumen which had been adsorbed to the brush borders.

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.

scholarly journals The hydrolysis of glycine oligopeptides by guinea-pig intestinal brush borders

1970 ◽  
Vol 119 (3) ◽  
pp. 20P-21P ◽  
Author(s):  
T J Peters ◽  
K Modha ◽  
C N C Drey
Keyword(s):  
Guinea Pig ◽  
Brush Borders ◽  
Hydrolysis Of

Histochemical and manometric studies of cholinesterases in mammalian kidney tissue

1963 ◽  
Vol 204 (1) ◽  
pp. 124-128 ◽  
Author(s):  
Gilbert L. Marx ◽  
M. Kathleen Carter
Keyword(s):  
Guinea Pig ◽  
Kidney Tissue ◽  
Histochemical Technique ◽  
Choline Esters ◽  
Hydrolysis Rates ◽  
Normal Rat ◽  
Manometric Studies ◽  
Hydrolysis Of ◽  
Manometric Technique ◽  
Rat Kidneys

The localization of cholinesterase in kidney tissue of rat, dog, mouse, rabbit, guinea pig, cat, and human has been attempted using the histochemical technique of Koelle. A cholinesterase is located in the glomeruli of rat, dog and mouse; and an aliesterase (eserine-resistant esterase) is located in the tubules of rat and dog. Other species, rabbit, cat, guinea pig, and human, stain very little for esterases in the parenchyma of the kidney using this technique. Nine of thirteen adrenalectomized rat kidneys stained less for cholinesterase in the glomeruli than normal rat kidneys. With the manometric technique hydrolysis rates for several choline esters, using homogenates of kidneys of most species mentioned, were determined. Very little correlation could be made between rates of hydrolysis of these choline esters and the staining obtained with the Koelle technique.

scholarly journals d-myoInositol 1:2-cyclic phosphate 2-phosphohydrolase

1972 ◽  
Vol 127 (1) ◽  
pp. 113-118 ◽  
Author(s):  
R. M. C. Dawson ◽  
N. Clarke
Keyword(s):  
Small Intestine ◽  
Rat Kidney ◽  
Kidney Cortex ◽  
Ph Optimum ◽  
Rat Kidney Cortex ◽  
Mammalian Tissues ◽  
Cyclic Phosphate ◽  
Hydrolysis Of

1. An enzyme in extracts of mammalian tissues catalyses the hydrolysis of d-myoinositol 1:2-cyclic phosphate (an intermediary in the enzymic degradation of phosphatidylinositol) to produce d-myoinositol 1-phosphate. 2. The enantiomorph of the substrate is not attacked. 3. The pH optimum is about 8.1–8.3 and the reaction is stimulated by Mg2+ ions. 4. Extracts from rat kidney cortex and medulla are very rich sources of the enzyme; brain, testis and small intestine contain intermediary activities, and other tissues contain very small amounts.

Electron microscopic study of the membrane glycoproteins in the rat kidney after cisplatin treatment

1989 ◽  
Vol 47 ◽  
pp. 912-913
Author(s):  
S.K. Aggarwal
Keyword(s):  
Alkaline Phosphatase ◽  
Rat Kidney ◽  
Light And Electron Microscopy ◽  
Kidney Tissue ◽  
Membrane Glycoproteins ◽  
Electron Microscopic ◽  
Before And After ◽  
Interstrand Cross Links ◽  
Cross Links

The proposed primary mechanism of action of the anticancer drug cisplatin (Cis-DDP) is through its interaction with DNA, mostly through DNA intrastrand cross-links or DNA interstrand cross-links. DNA repair mechanisms can circumvent this arrest thus permitting replication and transcription to proceed. Various membrane transport enzymes have also been demonstrated to be effected by cisplatin. Glycoprotein alkaline phosphatase was looked at in the proximal tubule cells before and after cisplatin both in vivo and in vitro for its inactivation or its removal from the membrane using light and electron microscopy.Outbred male Swiss Webster (Crl: (WI) BR) rats weighing 150-250g were given ip injections of cisplatin (7mg/kg). Animals were killed on day 3 and day 5. Thick slices (20-50.um) of kidney tissue from treated and untreated animals were fixed in 1% buffered glutaraldehyde and 1% formaldehyde (0.05 M cacodylate buffer, pH 7.3) for 30 min at 4°C. Alkaline phosphatase activity and carbohydrates were demonstrated according to methods described earlier.

Sign in / Sign up

Export Citation Format

Share Document