Adenosine triphosphate function

Phosphorus. Eighty-five percent of the phosphoms, the second most abundant element in the human body, is located in bones and teeth (24,35). Whereas there is constant exchange of calcium and phosphoms between bones and blood, there is very Httle turnover in teeth (25). The Ca P ratio in bones is constant at about 2 1. Every tissue and cell contains phosphoms, generally as a salt or ester of mono-, di-, or tribasic phosphoric acid, as phosphoHpids, or as phosphorylated sugars (24). Phosphoms is involved in a large number and wide variety of metaboHc functions. Examples are carbohydrate metaboHsm (36,37), adenosine triphosphate (ATP) from fatty acid metaboHsm (38), and oxidative phosphorylation (36,39). Common food sources rich in phosphoms are Hsted in Table 5 (see also Phosphorus compounds). 

Adenosine triphosphate, coupled reactions and. 1128-1129 function of, 157, 1127-1128 reaction with glucose, 1129 structure of, 157, 1044 S-Adenosylmethionine, from methionine, 669 function of, 382-383 stereochemistry of, 315 structure of, 1045 Adipic acid, structure of, 753 ADP, sec Adenosine diphosphate Adrenaline, biosynthesis of, 382-383 molecular model of, 323 slructure of, 24... 

Fig. 3-2 Chemical diagram of ATP (adenosine triphosphate). The three functional groups are the base adenosine (upper right), a five-carbon ribose sugar (middle), and three molecules of phosphate (left). Lines at bottom of sugar ring indicate hydroxyl groups.

Magnesium is the second most abundant intracellular cation. Magnesium serves as an essential cofactor for numerous enzymes and in many biochemical reactions, including reactions involving adenosine triphosphate (ATP).17 Magnesium disorders can be multifactorial and can be related to renal function, disease... 

F. H. Westheimer (1987) has provided a detailed survey of the multifarious ways in which phosphorus derivatives function in living systems (Table 4.7). The particular importance of phosphorus becomes clear when we remember that the daily turnover of adenosine triphosphate (ATP) in the metabolic processes of each human being amounts to several kilograms Phosphate residues bond two nucleotides or deoxynucleotides in the form of a diester, thus making possible the formation of RNA and DNA the phosphate always contains an ionic moiety, the negative charge of which stabilizes the diester towards hydrolysis and prevents transfer of these molecules across the lipid membrane. 

As bacterial transglucosidase is instrumental in the transfer of a D-glucose residue from one acceptor to another, so does yeast hexokinase 3 catalyze a transphosphorylation. The highly specific donator of a labile phosphate group is adenosine triphosphate (XX), the fermentable hexoses D-glucose, D-mannose and D-fructose functioning as acceptors. Hexokinase catalyzes the reaction... 

The main function of mitochondria is the generation of adenosine triphosphate (ATP) from adenosine diphosphate (ADP) and phosphate, which is achieved by energy transfer from oxidation of fuels. Some cells (e.g. hepatocytes) contain several thousand mitochondria, whereas others, such as erythrocytes, lack them entirely. 

ATP, adenosine triphosphate, provides the currency unit for energy in biochemical reactions (see Section 15.1.1) and is simply a triphosphate variant of a standard RNA nucleotide. It is, of course, the biosynthetic precursor for adenine-based units in RNA (see Section 14.2.5). As we have already seen (see Box 7.25), the functions of ATP can be related to hydrolytic reactions in the triphosphate (anhydride) part of the molecule. 

Fig. 1. The function of protein kinases [ADP (4), adenosine diphosphate ATP (3), adenosine triphosphate].

Reduction of l,10-phenanthroline-2-aldehyde to 1,10-phenanthroline-2-carbinol is efficiently accomplished by a dihydronicotinamide derivative in acetonitrile solution catalyzed by zinc ions. This was the first example of the reduction of an aldehyde by a NADH analog in a nonenzymic system. It also supports the catalytic function of the metal ion in the enzymic system.359 l,10-Phenanthroline-2-carbinol, obtained by sodium borohydride reduction of 2-carbomethoxy-1,10-phenanthroline, is phosphorylated by adenosine triphosphate in the presence of zinc ions.360... 

Kinetic studies of the nucleotide analogs, y-phenylpropyl di- and triphosphate, have been undertaken to define the role of the adenosine residue in the chemical and enzymic reactions of adenosine triphosphate. A catalytic function associated with binding of metal ions at the adenine nitrogens has been ascribed to the adenosine moiety in phosphate transfer reactions in which adenosine di- or triphosphates function as the phosphate source109-"2. The pH-rate profile (Fig. 6) for the hydrolysis of -y-phenylpropyl diphosphate... 

Riboflavin (vitamin B2) 6,7-dimethyl-9-(D-l-ribityl)isoalloxazine (63), was discovered as a coloring matter in milk in 1879, but its importance was not then realized. Deficiency causes lesions of the eye and of the angle of the mouth. Riboflavin is phosphorylated by adenosine triphosphate (ATP) to give riboflavin 5 -phosphate (flavinadenine mononucleotide, FMN) and then flavinadenine dinucleotide (FAD) (64 R = riboflavin). These function as prosthetic groups in a number of flavoproteins which are dehydrogenation catalysts by virtue of the oxidation-reduction properties of the isoalloxazine system. 

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