Phosphate stores

Phytate (myo-inositol hexaphosphate Fig. 15.3, structure 33) is found in many food species and can be considered as a phytochemical. Its role in the plant is primarily as a phosphate store in seeds, but it is found in other tissues as well, for example, tubers (Harland et al., 2004). Phytate and its hydrolysis products are anti-nutrients that chelate metal ions and thus reduce their bioavailability (Persson et al., 1998 House, 1999). This is particularly a problem with cereal grains, but pre-processing can improve mineral absorption from these foods (Agte and Joshi, 1997). There is some concern that high phytate foods could also contain higher levels of toxic heavy metals caused by natural accumulation. Plants also contain phytate-degrading enzymes that can also influence metal ion bioavailability (Viveros et al., 2000). 

This muscle phosphotransferase (EC 2.132) catalyzes the reversible rephosphorylation of ADP to form ATP (/.c., T eq = [ATP][Creatine]/([Creatine phosphate] [ADP]) = 30). In resting muscle, creatine phosphate is synthesized at the expense of abundant stores of ATP intracellular creatine phosphate stores often reach 50-60 mM. If ATP is suddenly depleted by muscle contraction, its product ADP is immediately converted back into ATP by the reverse of the creatine kinase reaction. Depending on the pH at which the enzyme is studied, the kinetic reaction can be either rapid equilibrium random or rapid equilibrium ordered. A-Ethylglycocyamine can also act as a substrate. 

Phosphate is critical to normal bone mineralization when phosphate stores are deficient, a clinical and pathologic picture resembling vitamin D-deficient rickets develops. However, affected children fail to respond to the usual doses of vitamin D used in the treatment of nutritional rickets. A defect in l,25(OH)2D production by the kidney has also been noted,... 

Mevalonic acid 5-pyrophosphate [1492-08-6] M 258,1, Purified by ion-exchange chromatography on Dowex-1 formate [Bloch et al. JBC 234 2595 7959], DEAE-cellulose [Skilletar and Kekwick, AB 20 171 7967], on by paper chromatography [Rogers et al. BJ99 381 7966]. Likely impurities are ATP and mevalonic acid phosphate. Stored as a dry powder or as a slightly alkaline (pH 7-9) soln at -20°. 

Phosphate is critical to normal bone mineralization when phosphate stores are deficient, a clinical and pathologic picture resembling vitamin D-deficient rickets develops. However, such children fail to respond to the usual doses of vitamin D employed in the treatment of nutritional rickets. A defect in l,25(OH)2D production by the kidney has also been noted, because the serum l,25(OH)2D levels tend to be low relative to the degree of hypophosphatemia observed. This combination of low serum phosphate and low or low-normal serum l,25(OH)2D provides the rationale for treating such patients with oral phosphate (1-3 g daily) and calcitriol (0.25-2 Mg daily). Reports of such combination therapy are encouraging in this otherwise debilitating disease. 

Creatine phosphate stores several times the amount of energy that is in ATP. 

The earliest (and probably the most important) proposed function for InsPg in plants is that of a phosphate store for seeds (Posternak, 1919). It is now known that InsPg exhibits strong antioxidant properties (Hawkins et al., 1993) and can cause complete inhibition of Fe3+-catalyzed hydroxyl-radical formation. Functions proposed more recently for InsPg include protein phosphatase inhibition (Larsson et al., 1997) and activation of PKC (Efanov et al., 1997). InsP6 was also found in the nucleus, and York and coworkers observed that InsPg may modulate mRNA transport out of the nucleus (York et al., 1999). 

A final point on the function of bacfer is that, given it contains a high level of phosphate (Table II) when loaded with iron, one of its roles may be as a phosphate store. 

W. W. Holt, M. F. Wendland, N. Derugin, C. Wolfe, M. Saeed, C. B. Higgins, Effects of nicardipine, a calcium antagonist, on myocardial salvage and high energy phosphate stores in reperfused myocardial injury, J Am Coll Cardiol 16, 1736-1744 (1990). 

Fructose intolerance A genetic deficiency in the liver enzyme aldolase B. The absence of this enzyme leads to a build up of fructose 1-phosphate and depletion of liver ATP and phosphate stores. 

NADP (nicotinamide adenine dinucleotide phosphate), storing the reducing power in the form of NADPH. The chlorophyll ion can regain an electron from a hydroxyl ion (OH ), which is also formed during the self-ionization of water, and the resulting hydroxyl radical (OH-, which has no charge) combines with others to form oxygen and water. 

Creatine phosphate, stored in the muscle, donates its high-energy phosphate to ADP to produce new supplies of ATP. 

For post-accident iodine control and to minimize corrosion of the stainless steel in the containment, the pH of the water in the IRWST and thus of the recirculated containment spray solution, is maintained at a minimum of 7.0 as recommended in SRP Section 6.5.2 and DTP MTEB 6-1. Disodium phosphate stored in baskets in the IRWST holdup volume becomes immersed in water during a LOCA and the resulting solution overflows into the IRWST. The stainless steel baskets, which are attached to the primary shield wall of the holdup volume, have a solid top and bottom with mesh sides to permit submergence of the disodium phosphate. The baskets are below the IRWST spillway but at a sufficient elevation to prevent an inadvertent submergence during normal operation. Access is provided to the baskets for inspection and sampling. 

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