Disease relevance of Phytate

• The structure of E. coli phytase in complex with phytate, the preferred substrate, reveals the binding mode and substrate recognition [1].
• This study was designed to determine whether specific WB fractions such as WB fiber, WB lipids, or phytic acid differentially affect colon carcinogenesis in a well-established colon cancer model [2].
• Faecal phytic acid and its relation to other putative markers of risk for colorectal cancer [3].
• Therefore the faecal phytic acid content of adenoma patients drawn from a placebo controlled calcium intervention trial was evaluated [3].
• In vivo suppression of hormone-refractory prostate cancer growth by inositol hexaphosphate: induction of insulin-like growth factor binding protein-3 and inhibition of vascular endothelial growth factor [4].

High impact information on Phytate

• Particular emphasis is put on milk proteins such as lactoferrin, casein, and whey proteins, but phytate in soy formula is also discussed [5].
• Polyphosphoinositols that block transmitter release, inositol 1,3,4,5-tetrakisphosphate (InsP4), inositol 1,3,4,5,6-pentakisphosphate (InsP5) and inositol 1,2,3,4,5,6-hexakisphosphate (InsP6), also block the assembly of the particle by preventing beta-SNAP from binding to synaptotagmin [6].
• Phospholipase C and two inositol polyphosphate (IP) kinases constitute a signaling pathway that regulates nuclear messenger RNA export through production of inositol hexakisphosphate (IP6) [7].
• Our previous studies in Saccharomyces cerevisiae defined an in vivo role for inositol hexakisphosphate (InsP6) and NPC-associated Gle1 in mRNA export [8].
• Here, we show that a PSV has within it a membrane-bound compartment containing crystals of phytic acid and proteins that are characteristic of a lytic vacuole [9].

Chemical compound and disease context of Phytate

• Technetium-99m phytate colloids formed in vitro and in vivo were examined as radioindicators for estimation of the volume of third-space fluid in an ovarian ascites model using C3HeB/FeJ mice [10].
• In previous studies, we have shown that inositol hexaphosphate (InsP6), a constituent of cereal diet, inhibited azoxymethane-induced experimental large intestinal cancer (LIC) in Fischer 344 rats [11].
• An androgen-independent androgen receptor function protects from inositol hexakisphosphate toxicity in the PC3/PC3(AR) prostate cancer cell lines [12].
• The aim of this study was to determine whether neutrophil accumulation would participate in the development of intimal hyperplasia after endothelial injury in mice, and whether d-myo-inositol hexakisphosphate (phytic acid) which inhibits the binding of L- and P-selectin to sialyl Lewis(X) could inhibit the development of intimal hyperplasia [13].
• Edema formation was also reduced by sulfatide (73.1%, 50 mg/kg) and inositol hexakisphosphate (InsP6) (72.9%, 30 mg/kg), which have been reported to block P-selectin-mediated neutrophil adhesion [14].

Biological context of Phytate

• We have developed transgenic mouse models to determine whether endogenous expression of phytase transgenes in the digestive tract of monogastric animals can increase the bioavailability of dietary phytate, a major but indigestible form of dietary phosphorus [15].
• Engineering crop plants to produce a heterologous phytase improves phosphate bioavailability and reduces phytic acid excretion [16].
• Phytases catalyze the hydrolysis of phytate and are able to improve the nutritional quality of phytate-rich diets [1].
• The development of 'low phytate' grain and legume genotypes could help advance our understanding of this biology, and when used in foods and feeds might help to reduce human malnutrition and reduce animal waste phosphorus [17].
• Binding of three additional calcium ions to low-affinity calcium binding sites at the top of the molecule turns on the catalytic activity of the enzyme by converting the highly negatively charged cleft into a favorable environment for the binding of phytate [18].

Anatomical context of Phytate

• Heparin, inositol hexaphosphate and inorganic sulfate strongly increased the trypsin resistance of the growth factor part of the fusion protein, indicating tight folding, and they prevented translocation of the fusion protein to the cytosol [19].
• The antisera immunoprecipitated a subpopulation of 35SO4-labeled HSPGs that were released from Schwann cells by incubation in medium containing phosphatidylinositol-specific phospholipase C (PI-PLC); smaller amounts of immunoprecipated HSPGs were also present in phytic acid extracts [20].
• Peripheral cell surface HSPGs were purified from phytic acid extracts of cultured neonatal rat sciatic nerve Schwann cells by anion exchange, gel filtration, and laminin-affinity chromatography [20].
• A continuous lysing and resealing procedure with erythrocytes permitted incorporation in these cells of inositol hexaphosphate (InsP6), a strong allosteric effector of Hb [21].
• Inositol hexakisphosphate (InsP(6)) is under metabolic control and serves as a signal in the pancreatic beta cell stimulus-secretion coupling by increasing Ca(2+)-channel activity and insulin exocytosis [22].

Associations of Phytate with other chemical compounds

• Long-term physiological effects of enhanced O2 release by inositol hexaphosphate-loaded erythrocytes [21].
• (RS)-2-cis, 4-trans-abscisic acid (ABA), a naturally occurring plant stress hormone, elicited rapid agonist-specific changes in myo-inositol hexakisphosphate (InsP(6)) measured in intact guard cells of Solanum tuberosum (n = 5); these changes were not reproduced by (RS)-2-trans, 4-trans-abscisic acid, an inactive stereoisomer of ABA (n = 4) [23].
• The order of efficiency was the same in both states, but with the opposite trend as inositol hexaphosphate > 2,3-diphosphoglycerate > Cl-. We detected intrinsic fluorescence from bound bezafibrate that introduced uncertainty in the comparison with other effectors [24].
• Inositol 1,3,4,5,6-pentakisphosphate and inositol hexakisphosphate were very potent inhibitors of 3-phosphatase (IC50 values of 1 and 0.5 microM, respectively); these polyphosphates did not affect 5-phosphatase activity at concentrations of up to 10 microM [25].
• Although many iron-chelating agents potentiate reactive oxygen formation and lipid peroxidation, phytic acid (abundant in edible legumes, cereals, and seeds) forms an iron chelate which greatly accelerates Fe2+-mediated oxygen reduction yet blocks iron-driven hydroxyl radical generation and suppresses lipid peroxidation [26].

Gene context of Phytate

• The synthesis of inositol hexakisphosphate. Characterization of human inositol 1,3,4,5,6-pentakisphosphate 2-kinase [27].
• Production of inositol hexakisphosphate (IP6) by Ipk1, the inositol-1,3,4,5,6-pentakisphosphate 2-kinase, is required for Gle1-mediated mRNA export in Saccharomyces cerevisiae cells [28].
• This pathway was present in wild-type and ipk2 null cells, albeit at low levels as compared with inositol hexakisphosphate synthesis [29].
• However, targeted inhibition of extracellular FGF-2 by overexpression of a secreted receptor mutant FGFR1(TM-) lacking the transmembrane domain failed to affect BMP-7 induced dendritic growth, as did treatment with the extracellular FGFR antagonist inositol hexakisphosphate [30].
• Inositol hexaphosphate represses telomerase activity and translocates TERT from the nucleus in mouse and human prostate cancer cells via the deactivation of Akt and PKCalpha [31].

Analytical, diagnostic and therapeutic context of Phytate

• SDS-PAGE analysis of proteins immunoprecipitated from extracts of [35S]methionine labeled Schwann cells demonstrated that the antisera precipitated an HSPG species that was present in the pool of proteins released by PI-PLC, with smaller amounts present in phytic acid extracts [20].
• Our results define a commercially viable strategy for the genetic engineering of phytate-free grain and provide insights into the role of inositol polyphosphate kinases in phosphate signaling biology [32].
• Titration of the carboxyhemoglobin tetramer-dimer equilibrium by inositol hexaphosphate [33].
• Different optical activity was also measured in the carbomonoxy derivatives of the beta subunits of hemoglobin A and S, the respective deoxy derivatives showed different circular dichroism spectra only in the presence of inositol hexaphosphate [34].
• After the addition of inositol hexaphosphate, the alpha subunits reacted about 1.5 times faster than the beta subunits in the first ligation step, but the overall rate of the first CO binding step was unchanged [35].

References