Phosphate biological importance

An example of a biologically important aide hyde is pyridoxal phosphate which is the active form of vitamin Bg and a coenzyme for many of the reac tions of a ammo acids In these reactions the ammo acid binds to the coenzyme by reacting with it to form an imine of the kind shown in the equation Re actions then take place at the ammo acid portion of the imine modifying the ammo acid In the last step enzyme catalyzed hydrolysis cleaves the imme to pyridoxal and the modified ammo acid... 

The biological importance of these compounds stems from their use as cofactors. Both nicotinamide and nicotinic acid ate building blocks for coen2yme I (Co I), nicotinarnide—adenine dinucleotide (NAE)) (3) and coen2yme II (Co II), nicotinarnide—adenine dinucleotide phosphate (NAE)P) (4) (2). 

Vasella has used deoxy-nitro sugars for the synthesis of various biologically important carbohydrates, and the radical nitromethyladon of deoxy-nitro sugars has been used for synthesis of fnictose 6-phosphate" and 6-C-methyl and 6-C-rhydroxymethyl analogiies of iV-acetylnenraitinic acid fsee Scheme7.2. ... 

Haley, F., and H. A. Lardy Phosphoric Esters of Biological Importance. VI. The Synthesis of D-Glucosamine 6-Phosphate and N-Acetyl-D-glucos-amine 6-Phosphate. J. Amer. chem. Soc. 78, 1393 (1956). 

Despite the biological importance of simple acyclic phosphate diesters, which include the nucleic acids, little detailed work had been done on their... 

An important class of naturally occurring anions are the nucleoside phosphates (i.e. nucleotides) present in nucleic acids, sugar nucleotides for glycosylation of oligosaccharides or proteins, activated forms of proteins and chemical mediators which play a central role in intracellular signals. Artificial phosphate receptors allow for detection and separation of biologically important compounds. However, most chemical receptors are soluble in solution and cannot be therefore separated easily from the solution binding the desired compound. 

It was found that the polymer exhibited selectivity towards phosphomonoester dianions. Less polar compounds were found to bind non-specifically to the polymer. The polymer was then used as a stationary phase for a HPLC column. A mixture containing dA, 5 -dAMP and 3, 5 -cAMP was thus separated. As expected, the retention time of 5 -AMP was larger than those for dA and 3, 5 -cAMP. The same was tme for other nucleotides compared to the corresponding nucleosides. When the Zn2+-free control polymer was used, all compounds were immediately eluted. The possibility to use polymer-anchored recognition units to separate biologically important phosphates was thus proved. 

Monosaccharides with modified structures are often biologically important. Examples include sugar phosphates, deoxy sugars, amino sugars, and ascorbic acid (vitamin C). 

C. Singh (1964). Interactions between cationic and anionic compounds of biological importance with special reference to inorganic condensed phosphates and polymeric antibiotics. Ind. J. Chem., 2, 67-81. 

A final group of biologically important phosphate compounds is the phosphoramidates, which are characterized by the structure shown in Figure III-33. Phosphocreatine, an important energy storage compound in muscle, and phosphohistidine, an intermediate in several enzyme reactions, are two examples (Fig. III-34). 

Bandurski, R. S., and Axelrod, B. (1951). The Chromatographic Identification of Some Biologically Important Phosphate Esters. J Biol Chem 193 405. 

The interest in the mechanisms of SchifF base hydrolysis stems largely from the fact that the formation and decomposition of SchifF base linkages play an important role in a variety of enzymatic reactions, for example, carbonyl transfers involving pyridoxal phosphate, aldol condensations, /3-decarboxylations and transaminations. The mechanisms for the formation and hydrolysis of biologically important SchifF bases, and imine intermediates, have been discussed by Bruice and Benkovic (1966) and by Jencks (1969). As the consequence of a number of studies (Jencks, 1959 Cordes and Jencks, 1962, 1963 Reeves, 1962 Koehler et al., 1964), the mechanisms for the hydrolysis of comparatively simple SchifF bases are reasonably well understood. From the results of a comprehensive kinetic investigation, the mechanisms for the hydrolysis of m- and p-substituted benzylidine-l,l-dimethylethylamines in the entire pH range (see, for example, the open circles in Fig. 13) have been discussed in terms of equations (23-26) (Cordes and Jencks, 1963) ... 

An extensive chemistry of phosphoms and oxygen exists, the preponderance of which deals with aqueous chemistry with great interest focused upon those of biological importance. A broad review of phosphoms oxygen chemistry is given in Phosphates. Reduced transition metal oxide phosphates and sihcates are discussed in Section 3.12. 

Phosphate minerals are found in rocks and living systems, and many biologically important molecules are phosphate esters (see Phosphorus Inorganic Chemistry). The balance between insoluble and soluble phosphates in the biosphere has been adversely affected by the use of phosphate fertilizers, water softeners and detergents. 

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