Adenosine triphosphate, complex formation with

Rechnitz, G.A. and Mohan, M.S., 1970, Potassium-adenosine triphosphate complex formation constant measured with ion-selective electrodes. Science 168 1460. 

Precipitation of the cytoplasm by the formation of complexes with phosphated entities, such as adenosine triphosphate and nucleic acids... 

The formation of the (Et0)3P0-nSi02-mH20 complex allows us to conclude that formation of complex silicon compounds with adenosine triphosphate and phosphate-containing organic reagents in natural systems would have such a mechanism. 

Chemical reactions between biochemical compounds are enhanced by biological catalysts called enzymes, which consist mostly or entirely of globular proteins. In many cases a cofactor is needed to combine with an otherwise inactive protein to produce the catalytically active enzyme complex. The two distinct varieties of cofactors are coenzymes, which are complex organic molecules, and metal ions. Enzymes catalyze six major classes of reactions 1) Oxidoreductases (oxidation-reduction reactions), 2) Transferases (transfer of functional groups), 3) Hydrolases (hydrolysis reactions), 4) Lyases (addition to double bonds, 5) Isomerases (isomerization reactions) and 6) Ligases (formation of bonds with ATP (adenosine triphosphate) cleavage) [1]. 

Association of the hydrophobic tails of membrane lipids leads, as depicted in Fig. 4.47a, to what Watkins [341] has described as polar discontinuities. Transition to the micellar state is considered to be essential to allow cell fusion to occur as the biomolecular leaflet is thermodynamically a stable system which would resist coalescence with similar structures. External influences can, however, induce phospholipid aggregation and can thus alter the permeability of cell membranes to water-soluble and oil-soluble species. Calcium ions, for example, induce inverse micelle formation in phospholipid systems [342]. Other metal ions also result in this transformation (Fig. 4.47b) addition of adenosine triphosphate (ATP) removes the metal and leads to a reversion to the normal micellar pattern. Maas and Coleman [343] have postulated that such transitions may have significance in nerve membrane operation. Metal-ATP-phospholipid complexes... 

When ATP and 2,4,6-trinitrobenzenesulphonic acid are mixed at pH 9.5, 2 - (or 3 -) 0-(2,4,6-trinitrophenyl)adenosine-5 -triphosphate (22) is formed, which binds to, and is hydrolysed by, heavy meromyosin. This ATP derivative exhibits reversible formation of a Meisenheimer complex, with pK 5.1. The... 

The nucleotide anhydride, adenosine 5 -triphosphate (24), when digested with aqueous barium hydroxide, gives a complex mixture containing such products as adenine, adenosine, adenosine 2 -, 3 -, and 5 -phosphates, adenosine 5 -pyrophosphate, and adenosine 2 (or 3 ),5 -diphosphate. - In addition, a nucleotide was foimd in this digest whose structure proved - to be that of adenosine 3 5 -cyclic phosphate (25). This component did not consume metaperiodate, and was degraded enzymically to adenosine 5 -phosphate (26) and adenosine 3 -phosphate (27), without the formation of adenosine 2 -phosphate. Hydrolysis of (25) with an acidic ion-exchange resin did, however, produce the 2 - and 3 -phosphates of adenosine. Compound (25) possessed only one phosphoryl dissociation, and showed a ratio of nucleoside to phosphate of 1 1, which, along with a molecular-... 

The toxicity of cyanide is attributed to its ability to inhibit enzyme reactions. The action of one such enzyme, cytochrome oxidase, essential for the respiration of cells is inhibited by cyanide ions. Cytochrome oxidase is a component of the mitochondrial electron transport system. It transfers electrons from cytochrome c to oxygen, forming water, while releasing sufficient free energy to permit the formation of adenosine 5 -triphosphate (ATP). The latter is essential for normal metabolic processes. Cyanide ion forms complexes with heavy metal ions such as iron and copper to stop electron transport and thus prevent ATP formation. Several enzyme reactions have been listed that cyanide can inhibit several enzyme reactions by forming complexes. 

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