scholarly journals Formation of methylphosphoryl inositol phosphates by extractions that employ methanol

1988 ◽  
Vol 253 (3) ◽  
pp. 703-710 ◽  
Author(s):  
J E Brown ◽  
M Rudnick ◽  
A J Letcher ◽  
R F Irvine
Keyword(s):  
Alkaline Phosphatase ◽  
Methanol Extract ◽  
Inositol Phosphates ◽  
Red Cell ◽  
Unknown Compound ◽  
Methyl Group ◽  
Phosphatidylinositol Bisphosphate ◽  
Inositol 1,4,5 Trisphosphate ◽  
Inositol Ring ◽  
Retinal Volume

Fixatives that contain methanol extract an unknown compound from several tissues including the retinas of squid (Loligo). We have determined that the compound probably contains (1) a myo-inositol ring that is phosphorylated in more than one position (including at the 5-hydroxyl), (2) a charged moiety that is not susceptible to alkaline phosphatase, and (3) a methyl group. We have found that the compound can be made by treating either phosphatidylinositol bisphosphate or human red cell ghosts with acidic methanol. We have confirmed the observation of Lips, Bross & Majerus [Proc. Natl. Acad. Sci. U.S.A. 85, 88-92] that the compound also can be made by methanolysis of inositol (cyclic 1:2,4,5)trisphosphate; however, we have not found inositol (cyclic 1:2,4,5)trisphosphate in either stimulated or unstimulated squid retinas. We tentatively identify the compound as (1-methylphosphoryl)inositol 4,5-bisphosphate formed by methanolysis of phosphatidylinositol 4,5-bisphosphate. By using this methanolysis to incorporate label from [14C]methanol, we have estimated the mass of inositol 1,4,5-trisphosphate in squid retinas to be approx. 30 mumol/l of retinal volume.

STEROIDSTRUKTUR UND LEBERTOXIZITÄT

1967 ◽  
Vol 54 (1) ◽  
pp. 73-84 ◽  
Author(s):  
H. L. Krüskemper ◽  
G. Noell
Keyword(s):  
Alkaline Phosphatase ◽  
Liver Function ◽  
Blood Coagulation ◽  
Electrophoretic Pattern ◽  
Coagulation Factors ◽  
Blood Coagulation Factors ◽  
Methyl Group ◽  
Liver Functions ◽  
Male Subjects ◽  
Androstane Derivatives

ABSTRACT In male subjects investigations have been carried out regarding the effect of C1- and C17-methylated androstane derivatives (20 mg per day, orally, two weeks) on liver functions (parameters: activities of GPT, GOT, alkaline phosphatase and cholinesterase in serum; electrophoretic pattern; blood coagulation factors V, VII, X and prothrombin; BSP-retention). In addition to the well known hepatotropic action of 17α-alkylated C-19-steroids a quasi-axial 1α-methyl configuration (in 1α-methylandrost-2-en-17β-ol) definitely increased BSP-retention and several coagulation factors. These steroid effects decreased gradually when a methyl group was introduced in C1 equatorially (1-methylandrost-1-en-17β-ol-3-one) or quasi-equatorially (1β-methylandrost-2-en-17β-ol), the latter compound completely lacking from any influence on parameters of liver function under investigation.

Phosphate, inositol and polyphosphates

2016 ◽  
Vol 44 (1) ◽  
pp. 253-259 ◽  
Author(s):  
Thomas M. Livermore ◽  
Cristina Azevedo ◽  
Bernadett Kolozsvari ◽  
Miranda S.C. Wilson ◽  
Adolfo Saiardi
Keyword(s):  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
High Energy ◽  
Inorganic Polyphosphate ◽  
Covalent Bonds ◽  
Polymeric Form ◽  
Phosphodiester Bond ◽  
Signalling Molecules ◽  
Inositol Ring ◽  
Phosphate Groups

Eukaryotic cells have ubiquitously utilized the myo-inositol backbone to generate a diverse array of signalling molecules. This is achieved by arranging phosphate groups around the six-carbon inositol ring. There is virtually no biological process that does not take advantage of the uniquely variable architecture of phosphorylated inositol. In inositol biology, phosphates are able to form three distinct covalent bonds: phosphoester, phosphodiester and phosphoanhydride bonds, with each providing different properties. The phosphoester bond links phosphate groups to the inositol ring, the variable arrangement of which forms the basis of the signalling capacity of the inositol phosphates. Phosphate groups can also form the structural bridge between myo-inositol and diacylglycerol through the phosphodiester bond. The resulting lipid-bound inositol phosphates, or phosphoinositides, further expand the signalling potential of this family of molecules. Finally, inositol is also notable for its ability to host more phosphates than it has carbons. These unusual organic molecules are commonly referred to as the inositol pyrophosphates (PP-IPs), due to the presence of high-energy phosphoanhydride bonds (pyro- or diphospho-). PP-IPs themselves constitute a varied family of molecules with one or more pyrophosphate moiety/ies located around the inositol. Considering the relationship between phosphate and inositol, it is no surprise that members of the inositol phosphate family also regulate cellular phosphate homoeostasis. Notably, the PP-IPs play a fundamental role in controlling the metabolism of the ancient polymeric form of phosphate, inorganic polyphosphate (polyP). Here we explore the intimate links between phosphate, inositol phosphates and polyP, speculating on the evolution of these relationships.

scholarly journals Alkaline Phosphatase Is Associated with Red Cell Alloimmunization in the Pulmonary Hypertension and Hypoxic Response (PUSH) Sickle Cell Disease Cohort

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 20-20
Author(s):  
Victoria Brooks ◽  
Oluwalonimi Adebowale ◽  
Victor R. Gordeuk ◽  
Sergei Nekhai ◽  
James G. Taylor
Keyword(s):  
Risk Factors ◽  
Alkaline Phosphatase ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Research Funding ◽  
Severe Disease ◽  
Case Control ◽  
Red Cell ◽  
Cell Disease ◽  
History Of

Background: Blood transfusion is a common therapy for sickle cell disease (SCD). Although, highly effective, a major limitation is development of alloantibodies to minor blood group antigens on donor red cells. Alloimmunization has a prevalence of 2-5% for transfusions in the general population, but it is significantly higher in SCD. Risk factors for alloimmunization have been poorly characterized, although number of lifetime transfusions is an important risk factor. Alloimmunization has been clinically observed in children with a prevalence of about 7%. With development of each antibody, blood donor matching becomes increasingly difficult and expensive with an increased risk for transfusion reactions and diminished availability of compatible red cell units for treatment of SCD. The ability to identify risk factors for developing alloantibodies would be beneficial for clinicians. To identify markers for alloimmunization in SCD, we have analyzed children and adults who developed this complication. Methods: We analyzed The Pulmonary Hypertension and Hypoxic Response in Sickle Cell Disease (PUSH) study, which enrolled n=468 pediatric and n=59 adult SCD subjects. In both children and adults, alloimmunization cases were defined as a history of at least 1 alloantibody. Controls in both cohorts were defined as subjects with no history of alloantibodies and receipt of more than 10 lifetime red cell transfusions. All others within the study who did not meet these criteria were assigned to a third comparison group. To identify differences between cases, controls and all others, we performed univariate analyses (using ANOVA or Kruskal Wallace where appropriate) for clinical parameters and laboratories. Case control comparisons were also performed for selected variables and plasma levels for 11 cytokines. Results were further analyzed using regression modeling. Results: The overall prevalence of alloimmunization was 7.3% among children (34/468 subjects; median age 12, range 3-20 years) compared to 28.8% in adults (17/59 subjects; median age 37, range 18-73 years). When only considering those with >10 lifetime transfusions, the prevalence was considerably higher at 29.3% and 54.8% in children and adults, respectively. At the same time, 8 pediatric (23.5%) and 5 adult (29.4%) alloimmunization cases had received fewer than 10 transfusions. In a 3-way pediatric cohort comparison (cases, controls and all others), risk factors associated with alloimmunization included SS genotype, older age and markers of more severe disease (higher ferritin, WBCs, platelets and total bilirubin). Comparison of cases to controls showed alkaline phosphatase (P=0.05) was significantly lower in cases, whereas AST (P=0.02) was significantly higher even with adjustment for age. Levels of plasma cytokines MCP-1 (P=0.01) and IFNgamma (P=0.08) were lower in cases from a subset of the pediatric cohort. In adults, only 4/59 (6.8%) subjects had never received a lifetime transfusion (all non-SS). In the adult 3-way comparisons, only SS genotype and higher ferritin were associated with alloimmunization. The adult case control analysis showed higher absolute monocyte count (P=0.02), absolute eosinophil count (P=0.04) and absolute basophil count (P=0.008) in association with alloimmunization cases. In addition, alkaline phosphatase was again significantly lower among cases (P=0.02) as seen in the pediatric cohort. There were no significant differences in cytokine levels among adults. Conclusions: When considering only transfused SCD patients, the prevalence of alloimmunization is higher than 30%. As seen in prior studies, higher lifetime red cell transfusions are an important risk factor especially among adults where most patients have received transfusions. Children who develop alloantibodies appear to have laboratory markers of more severe disease, but this is not observed in adults. A novel association observed across both pediatric and adult subjects is a significantly lower serum alkaline phosphatase in those with alloantibodies. The results of this study suggest a need for improved tracking of red cell transfusion therapy in the US for SCD patients due to a high prevalence of alloimmunization. Further study is also needed to elucidate the significance of the alkaline phosphatase association. Disclosures Gordeuk: CSL Behring: Consultancy, Research Funding; Global Blood Therapeutics: Consultancy, Research Funding; Novartis: Consultancy; Ironwood: Research Funding; Imara: Research Funding.

Incorporation of human liver and placental alkaline phosphatases into liposomes and membranes is via phosphatidylinositol

1990 ◽  
Vol 68 (9) ◽  
pp. 1112-1118 ◽  
Author(s):  
Lee Kihn ◽  
Dorothy Rutkowski ◽  
Robert A. Stinson
Keyword(s):  
Alkaline Phosphatase ◽  
Phospholipase C ◽  
Human Liver ◽  
Red Cell ◽  
Osteosarcoma Cells ◽  
Alkaline Phosphatases ◽  
Membrane Anchor ◽  
Gradient Gel Electrophoresis ◽  
Triton X ◽  
Phosphatidylinositol Phospholipase C

As assessed by incorporation into liposomes and by adsorption to octyl-Sepharose, the integrity of the membrane anchor for the purified tetrameric forms of alkaline phosphatase from human liver and placenta was intact. Any treatment that resulted in a dimeric enzyme precluded incorporation and adsorption. An intact anchor also allowed incorporation into red cell ghosts. The addition of hydrophobic proteins inhibited incorporation into liposomes to varying degrees. Alkaline phosphatase was 100% releasable from liposomes and red cell ghosts by a phospholipase C specific for phosphatidylinositol. There was no appreciable difference in the rates of release of placental and liver alkaline phosphatases, although both were approximately 250 × slower in liposomes and 100 × slower in red cell ghosts than the enzyme's release from a suspension of cultured osteosarcoma cells. Both enzymes were released by phosphatidylinositol phospholipase C as dimers and would not reincorporate or adsorb to octyl-Sepharose. However, the enzyme incorporated, resolubilized by Triton X-100, and cleansed of the detergent by butanol treatment was tetrameric by gradient gel electrophoresis, was hydrophobic, and could reincorporate into fresh liposomes. A monoclonal antibody to liver alkaline phosphatase inhibited the enzyme's incorporation into liposomes, and abolished its release from liposomes and its conversion to dimers by phosphatidylinositol phospholipase C.Key words: alkaline phosphatase, liposome, phosphatidylinositol, membrane anchor.

Phospholipase Resistance of the Glycosyl-Phosphatidylinositol Membrane Anchor on Human Alkaline Phosphatase

1992 ◽  
Vol 38 (12) ◽  
pp. 2517-2525 ◽  
Author(s):  
Y W Wong ◽  
M G Low
Keyword(s):  
Alkaline Phosphatase ◽  
Cell Surface ◽  
Human Cell Lines ◽  
Membrane Anchor ◽  
Gpi Anchor ◽  
Glycosyl Phosphatidylinositol ◽  
In Vivo Release ◽  
Mammalian Tissues ◽  
Inositol Ring

Abstract Alkaline phosphatase (ALP) is attached to the cell surface in mammalian tissues via a glycosyl-phosphatidylinositol (GPI) anchor and can be released from the membrane by GPI-specific phospholipases. In a range of cultured human cell lines, however, the sensitivity of ALP to phospholipases was observed to be variable in magnitude (approximately 20-90%). The mechanism of phospholipase resistance was explored with phospholipases of different bond specificities. The results suggest that phospholipase resistance is the result of acylation of the inositol ring in the GPI anchor. The occurrence of phospholipase-resistant forms of ALP may have important implications for the in vivo release and disposition of plasma ALP.

scholarly journals Separation of multiple isomers of inositol phosphates formed in GH3 cells

1987 ◽  
Vol 242 (2) ◽  
pp. 361-366 ◽  
Author(s):  
N M Dean ◽  
J D Moyer
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Inositol Phosphates ◽  
Thyrotropin Releasing Hormone ◽  
Gh3 Cells ◽  
Releasing Hormone ◽  
Inositol 1 ◽  
Trh Stimulation ◽  
Inositol 1,4,5 Trisphosphate

A high-performance-liquid-chromatography (h.p.l.c.) separation was developed, which resolves isomers of inositol monophosphate (IP), inositol bisphosphate (IP2), and inositol trisphosphate (IP3) in a single run. In GH3 cells labelled with [3H]inositol, treated with Li+ and thyrotropin-releasing hormone (TRH), radiolabelled components identified as inositol 1-phosphate (I1P), inositol 2-phosphate (I2P), inositol 4-phosphate (I4P), inositol 1,4-bisphosphate [I(1,4)P2], inositol 1,3,4-trisphosphate [I(1,3,4)P3] and inositol 1,4,5-trisphosphate [I(1,4,5)P3] are present, as are multiple unidentified IP2 peaks. After TRH stimulation, both I1P and I4P increase, the increase in I4P preceding that of I1P; I(1,4)P2 and an unknown IP2 increase; and both I(1,3,4)P3 and I(1,4,5)P3 increase, the increase in I(1,4,5)P3 being rapid and transient, whereas the increase in I(1,3,4)P3 is slower and more sustained. The most rapidly appearing inositol phosphates produced after TRH stimulation are I(1,4)P2 and I(1,4,5)P3.

scholarly journals Relationships between the degree of cross-linking of surface immunoglobulin and the associated inositol 1,4,5-trisphosphate and Ca2+ signals in human B cells

1992 ◽  
Vol 284 (2) ◽  
pp. 447-455 ◽  
Author(s):  
F M McConnell ◽  
S B Shears ◽  
P J L Lane ◽  
M S Scheibel ◽  
E A Clark
Keyword(s):  
B Cells ◽  
Tyrosine Kinase ◽  
Phospholipase C ◽  
Inositol Phosphates ◽  
Inositol Phosphate ◽  
Cross Linking ◽  
Immunoglobulin Receptor ◽  
Surface Immunoglobulin ◽  
Human B Cells ◽  
Inositol 1,4,5 Trisphosphate

Cross-linking of surface immunoglobulin (Ig) receptors on human B cells leads to the activation of a tyrosine kinase. The activated tyrosine kinase subsequently phosphorylates a number of substrates, including phospholipase C-gamma. This enzyme breaks down phosphoinositol bisphosphate to form two intracellular messengers, diacylglycerol and inositol 1,4,5-trisphosphate, leading to the activation of protein kinase C and the release of intracellular Ca2+ respectively. We have used h.p.l.c. and flow cytometry to measure accurately the inositol phosphate turnover and Ca2+ release in anti-Ig-stimulated human B cells. In particular, we have examined the effect of dose of the cross-linking antibody on the two responses. The identity of putative messenger inositol phosphates has been verified by structural analysis, and the amounts of both inositol phosphates and Ca2+ present have been quantified. In the Ramos Burkitt lymphoma, which is very sensitive to stimulus through its Ig receptors, both inositol phosphate production and Ca2+ release were found to be related to the dose of anti-Ig antibody applied. This suggests that phospholipase C-mediated signal transduction in human B cells converts the degree of cross-linking of the immunoglobulin receptor quantitatively into intracellular signals.

scholarly journals Actions of inositol phosphates on Ca2+ pools in guinea-pig hepatocytes

1984 ◽  
Vol 224 (3) ◽  
pp. 741-746 ◽  
Author(s):  
G M Burgess ◽  
R F Irvine ◽  
M J Berridge ◽  
J S McKinney ◽  
J W Putney
Keyword(s):  
Endoplasmic Reticulum ◽  
Guinea Pig ◽  
Inositol Phosphates ◽  
Second Messenger ◽  
Release Mechanism ◽  
Specific Receptor ◽  
Rapid Release ◽  
Inositol 1,4,5 Trisphosphate

In permeabilized hepatocytes, inositol 1,4,5-trisphosphate, inositol 2,4,5-trisphosphate and inositol 4,5-bisphosphate induced rapid release of Ca2+ from an ATP-dependent, non-mitochondrial vesicular pool, probably endoplasmic reticulum. The order of potency was inositol 1,4,5-trisphosphate greater than inositol 2,4,5-trisphosphate greater than inositol 4,5-bisphosphate. The Ca2+-releasing action of inositol 1,4,5-trisphosphate is not inhibited by high [Ca2+], nor is it dependent on [ATP] in the range of 50 microM-1.5 mM. These results suggest a role for inositol 1,4,5-trisphosphate as a second messenger in hormone-induced Ca2+ mobilisation, and that a specific receptor is involved in the Ca2+-release mechanism.

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