Release of Ectoenzymes from Small Intestine Brush Border Membranes of Mice by Phospholipases

Itami, Chisako; Taguchi, Ryo; Ikezawa, Hiroh; Nakabayashi, Toshikatsu

doi:10.1271/bbb.61.336

Cited by 9 publications

(4 citation statements)

References 8 publications

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“…It was proposed that the GPI anchor of aminopeptidase P is sterically hindered, and only accessible to PI-PLC after disturbance of the membrane structure. Similar arguments were used to explain the PI-PLC resistance of alkaline phosphatase in mouse brushborder membrane vesicles [31].…”

Section: Table 3 Release Of Detergent-solubilized and Membrane-bound mentioning

confidence: 83%

Release of the glycosylphosphatidylinositol-anchored enzyme ecto-5′-nucleotidase by phospholipase C: catalytic activation and modulation by the lipid bilayer

Lehto

Sharom

1998

Biochemical Journal

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Many hydrolytic enzymes are attached to the extracellular face of the plasma membrane of eukaryotic cells by a glycosylphosphatidylinositol (GPI) anchor. Little is currently known about the consequences for enzyme function of anchor cleavage by phosphatidylinositol-specific phospholipase C. We have examined this question for the GPI-anchored protein 5h-nucleotidase (5h-ribonucleotide phosphohydrolase ; EC 3.1.3.5), both in the native lymphocyte plasma membrane, and following purification and reconstitution into defined lipid bilayer vesicles, using Bacillus thuringiensis phosphatidylinositol-specific phospholipase C (PI-PLC). Membrane-bound, detergentsolubilized and cleaved 5h-nucleotidase all obeyed MichaelisMenten kinetics, with a K m for 5h-AMP in the range 11-16 µM. The GPI anchor was removed from essentially all 5h-nucleotidase molecules, indicating that there is no phospholipase-resistant pool of enzyme. However, the phospholipase was much less efficient at cleaving the GPI anchor when 5h-nucleotidase was present in detergent solution, dimyristoyl phosphatidylcholine, egg phosphatidylethanolamine and sphingomyelin, compared

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Section: Table 3 Release Of Detergent-solubilized and Membrane-bound mentioning

confidence: 83%

Release of the glycosylphosphatidylinositol-anchored enzyme ecto-5′-nucleotidase by phospholipase C: catalytic activation and modulation by the lipid bilayer

Lehto

Sharom

1998

Biochemical Journal

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“…IALP regulates Ca absorption in the jejunum and duodenum and its activity and mRNA expression are dependent on vitamin D [14,15,[25][26][27]. Absence of estrogen also decreases IAP expression and the activity of IALP [12,13].…”

Section: Discussionmentioning

confidence: 99%

Coumestrol Decreases Intestinal Alkaline Phosphatase Activity in Post-delivery Mice but does not Affect Vitamin D Receptor and Calcium Channels in Post-delivery and Neonatal Mice

Kirihata

Kawarabayashi

Imanishi

et al. 2008

Journal of Reproduction and Development

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Abstract. In this study, we investigated the effects of administration of coumestrol during pregnancy on calcium (Ca) metabolism in post-delivery maternal and neonatal mice. From 6.5 to 16.5 days post coitus (dpc), pregnant females were administered daily doses of coumestrol (200 µg/kg body weight/day). One day after parturition, blood samples and the kidneys, liver, jejunum and duodenum were obtained from each of maternal mouse, and blood samples and the kidneys and liver were obtained from neonatal mice. Coumestrol did not have any significant effect on the Ca and inorganic phosphorus concentrations in the sera of the maternal and neonatal mice. No notable effects of coumestrol were observed in relation to Vitamin D receptor expression in the maternal and neonatal mice by immunohistochemical analysis. Coumestrol did not affect the Vitamin D receptor and epithelial calcium channel1 and 2 mRNA levels in any of the organs investigated. Enzyme histochemical analysis showed that coumestrol decreased intestinal alkaline phosphatase activity in the maternal jejunum and duodenum. In the duodenum, coumestrol decreased expression of intestinal alkaline phosphatase, c-fos and vascular endothelial growth factor at the mRNA level. However, we did not observe any significant effects of coumestrol on the expression of these genes. In conclusion, coumestrol decreased intestinal alkaline phosphatase activity in the small intestines of maternal mice at the level used in the present study, and the mechanisms underlying this effect are different for the jejunum and duodenum. Key words: Coumestrol, Delivery, Epithelial calcium channels, Intestinal alkaline phosphatase, Mouse, Vitamin D receptor (J. Reprod. Dev. 54: [35][36][37][38][39][40][41] 2008) xogenous endocrine disruptors (EDs) are chemicals that exist in our environment and disrupt normal endocrine systems. Phytoestrogens, candidates of EDs, are plant-derived compounds that have a similar chemical structure to endogenous estrogen and the potential to mimic estrogen activity [1]. These chemicals can compete with 17β-estradiol for binding to estrogen receptors (ERs), although their relative affinity to ERs and transcription activity are substantially less than those of endogenous estrogens. Phytoestrogens can act as both estrogen agonists and antagonists [2]. Legumes are rich sources of phytoestrogens, and our foods and forage crops also contain them. There are several health benefits from these compounds, and phytoestrogens may help to prevent carcinomas, including breast, prostate and colon cancer, heart diseases, osteoporosis and menopausal disorders [2]. Thus, it is expected that phytoestrogens can be used to improve the health of humans, to prevent sickness and for estrogen replacement therapy (ERT). However, in the mid-20 th century, sheep fed a diet of predominately subterranean clover suffered from a reproductive disorder that reduced their lambing rates and produced abnormalities in the reproductive organs, permanent infertility, prolapsed uterus and maternal dys...

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“…This implies the occurrence of Ap n A hydrolases unrelated to the presently identified members of the E‐NPP family. Also unexplained is the release of Ap n A‐hydrolyzing enzyme activity by phosphatidyl inositol‐specific phospholipase C, suggesting membrane anchorage via a glycosylphosphatidyl inositol‐anchor [20,55–57].…”

Section: Discussionmentioning

confidence: 99%

Hydrolysis of diadenosine polyphosphates by nucleotide pyrophosphatases/phosphodiesterases

Vollmayer

Clair

Goding

et al. 2003

European Journal of Biochemistry

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Diadenosine polyphosphates (Ap n As) act as extracellular signaling molecules in a broad variety of tissues. They were shown to be hydrolyzed by surface-located enzymes in an asymmetric manner, generating AMP and Ap n-1 from Ap n A. The molecular identity of the enzymes responsible remains unclear. We analyzed the potential of NPP1, NPP2, and NPP3, the three members of the ecto-nucleotide pyrophosphatase/phosphodiesterase family, to hydrolyze the diadenosine polyphosphates diadenosine 5¢,5¢¢¢-P 1 ,P 3 -triphosphate (Ap 3 A), diadenosine 5¢,5¢¢¢-P 1 ,P 4 -tetraphosphate (Ap 4 A), and diadenosine 5¢,5¢¢¢-P 1 ,P 5 -pentaphosphate, (Ap 5 A), and the diguanosine polyphosphate, diguanosine 5¢,5¢¢¢-P 1 ,P 4 -tetraphosphate (Gp 4 G). Each of the three enzymes hydrolyzed Ap 3 A, Ap 4 A, and Ap 5 A at comparable rates. Gp 4 G was hydrolyzed by NPP1 and NPP2 at rates similar to Ap 4 A, but only at half this rate by NPP3. Hydrolysis was asymmetric, involving the a,b-pyrophosphate bond. Ap n A hydrolysis had a very alkaline pH optimum and was inhibited by EDTA. Michaelis constant (K m ) values for Ap 3 A were 5.1 lM, 8.0 lM, and 49.5 lM for NPP1, NPP2, and NPP3, respectively. Our results suggest that NPP1, NPP2, and NPP3 are major enzyme candidates for the hydrolysis of extracellular diadenosine polyphosphates in vertebrate tissues.Keywords: diadenosine polyphosphate; diguanosine polyphosphate; ectonucleotidase; nucleotide pyrophosphatase; nucleotide phosphodiesterase.Diadenosine polyphosphates [adenosine-(5¢)-oligophospho-(5¢)-adenosines, Ap n As] comprise two adenosine residues linked together by a polyphosphate chain through phosphoester bonds at their ribose 5¢ carbons. Ap n As are present intracellularly in prokaryotic and eukaryotic cells [1]. Recently, this group of nucleotides has attracted considerable interest because its members act as extracellular signaling molecules in a broad variety of tissues [2,3]. They are involved, for example, in the modulation of synaptic transmission and sensory nerve function [2-4], inhibition of platelet aggregation [5], or in the control of vascular tone [6][7][8][9]. Vasoactive effects were also observed with adenosine polyphosphoguanosines (Ap n Gs) and diguanosine polyphosphates (Gp n Gs) [10].The diadenosine polyphosphates diadenosine 5¢,5¢¢¢-P 1 ,P 3 -triphosphate (Ap 3 A), diadenosine 5¢,5¢¢¢-P 1 ,P 4 -tetraphosphate (Ap 4 A), and diadenosine 5¢,5¢¢¢-P 1 ,P 5 -pentaphosphate (Ap 5 A) are stored in chromaffin granules at millimolar concentrations together with noradrenaline and other nucleotides such as ATP and ADP [11,12]. In cholinergic synaptic vesicles, Ap 4 A and Ap 5 A were found to be co-stored with acetylcholine [13]. They can be released from secretory cells in a stimulus-dependent manner [2]. Besides the adrenal medulla, platelets are thought to represent the main source of Ap n As in blood. Stimulated platelets release, from their storage granules, a mixture of Ap n As (up to Ap 7 A), as well as Ap n Gs and Gp n Gs, together with ATP, ADP and serotonin [14,15]. Ap n ...

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Release of Ectoenzymes from Small Intestine Brush Border Membranes of Mice by Phospholipases

Cited by 9 publications

References 8 publications

Release of the glycosylphosphatidylinositol-anchored enzyme ecto-5′-nucleotidase by phospholipase C: catalytic activation and modulation by the lipid bilayer

Release of the glycosylphosphatidylinositol-anchored enzyme ecto-5′-nucleotidase by phospholipase C: catalytic activation and modulation by the lipid bilayer

Coumestrol Decreases Intestinal Alkaline Phosphatase Activity in Post-delivery Mice but does not Affect Vitamin D Receptor and Calcium Channels in Post-delivery and Neonatal Mice

Hydrolysis of diadenosine polyphosphates by nucleotide pyrophosphatases/phosphodiesterases

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