Calcium complexes amino acids

Calcium complexes amino acids, 33 arsine oxides, 9 bipyridyl, 13 crown ethers, 39 dimethylphthalate, 16 hydrates, 7, ionophores, 66 peptides, 33 phosphines, 9 pyridine oxide, 9 Schiff bases, 29 urea,9 Calixarenes... 

Most chemical and reaction path models currently account only for the aqueous carboxylic acids and their cation complexes, amino acids, some liquid hydrocarbons, alcohols, and certain other compounds entered into the data base for project-specific purposes. Adsorption of trace metals onto solid humic substances, for example, requires the user to create a fictitious solid and use an empirical adsorption coefficient. Scattered reports of carboxylic acid solids such as calcium oxalate (Marlowe 1970 Naumov et al. 1971 Galimov et al. 1975 Graustein et al. 1977 Campbell and Roberts 1986) emphasize the necessity to perform sensitivity analyses on the formation of such solids and indicate another area of uncertainty in the interpretation of chemical and reaction path model results. 

A 0-9% salt solution is considered to be isotonic with blood. Other electrolytes present include bicarbonate ions (HCOj ) and small amounts of potassium, calcium, magnesium, phosphate, sulphate and organic acid ions. Included among the complex compounds and present in smaller amounts are phospholipids, cholesterols, natural fats, proteins, glucose and amino acids. Under normal conditions the extracellular body fluid is slightly alkaline with a pH of 7-4. ... 

Calcium-binding proteins, 6, 564, 572, 596 intestinal, 6, 576 structure, 6, 573 Calcium carbonate calcium deposition as, 6, 597 Calcium complexes acetylacetone, 2, 372 amides, 2,164 amino acids, 3, 33 arsine oxides, 3, 9 biology, 6, 549 bipyridyl, 3, 13 crown ethers, 3, 39 dimethylphthalate, 3, 16 enzyme stabilization, 6, 549 hydrates, 3, 7 ionophores, 3, 66 malonic acid, 2, 444 peptides, 3, 33 phosphines, 3, 9 phthalocyanines, 2,863 porphyrins, 2, 820 proteins, 2, 770 pyridine oxide, 3,9 Schiff bases, 3, 29 urea, 3, 9... 

There are problems as well in the absorption of certain drugs in the presence of specific food components. L-Dopa absorption may be inhibited in the presence of certain amino acids formed from the digestion of proteins [43], The absorption of tetracycline is reduced by calcium salts present in dairy foods and by several other cations, including magnesium and aluminum [115-117], which are often present in antacid preparations. In addition, iron and zinc have been shown to reduce tetracycline absorption [118], Figure 17 illustrates several of these interactions. These cations react with tetracycline to form a water-in-soluble and nonabsorbable complex. Obviously, these offending materials should not be co-administered with tetracycline antibiotics. 

The variety of prebiotic organic reactions seems to be almost unlimited. Strasdeit et al. (2002) from the University of Hohenheim (Germany) reported the synthesis of zinc and calcium complexes of the amino acids valine and isovaline. They assume that these could have had a certain significance on the mineral-rich primeval Earth on heating to 593 K under nitrogen, valine was converted to the corresponding cyclic dipeptide. 

During the last decade, a number of investigators have attempted to elucidate the mechanism by which protein consumption induces hypercalciuria. In our previous research, the calciuria could not be explained by increased intestinal absorption of calcium, complexing with sulfur amino acids, or urinary acid production. 

Purification entails use of an immunoaffinity column containing immobilized murine antifactor VII antibody. It is initially produced as an unactivated, single chain 406 amino acid polypeptide, which is subsequently proteolytically converted into the two-chain active factor Vila complex. After sterilization by filtration, the final product is aseptically filled into its final product containers and freeze-dried. The excipients present in the product include sodium chloride, calcium chloride, polysorbate 80, mannitol and glycylglycine. When freeze-dried in the presence of these stabilizing substances and stored under refrigerated conditions, the product displays a shelf-life of at least 2 years. It has proved effective in the treatment of serious bleeding events in patients displaying anti-factor VIII or IX antibodies. 

FIGURE 13—30. Icon of acamprosate. A structural analogue of the amino acid taurine, acamprosate reduces the excitatory actions of glutamate at the NMDA—calcium channel complex. 

In conclusion, troponin binds Ca2+ in six-fold coordination and all oxygen ligands are provided from amino acids. No water is needed for the coordination complex. Aspartic acid and glutamic acid occupy key positions in the four calcium binding regions of the molecule. Transfer of calcium to tropomyosin and the actin filament during contraction is achieved by coordination changes. 

The amino acid sequence of fibrillin-1 is predominantly hydrophilic, even in the presence of bound calcium (Sherratt et al, 2004). In addition, fibrillin-1 has 14 potential N-glycosylation sites that may contribute to the hydrophilic nature of fibrillin-1, since complex N-linked oligosaccharides are negatively charged if they contain sialic acid. Additional regions of increased hydrophilicity may be contributed by other microfibril components (see Section III below). 

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