Amino acid nucleotides

To date, the most extensively studied polyboron hydride compounds in BNCT research have been the icosahedral mercaptoborane derivatives Na2[B22H22SH] and Na [(B22H22S)2], which have been used in human trials with some, albeit limited, success. New generations of tumor-localizing boronated compounds are being developed. The dose-selectivity problem of BNCT has been approached using boron hydride compounds in combination with a variety of deUvery vehicles including boronated polyclonal and monoclonal antibodies, porphyrins, amino acids, nucleotides, carbohydrates, and hposomes. Boron neutron capture therapy has been the subject of recent reviews (254). 

Amino acids, Nucleotides, Monosaccharides, Fatty acids, Glycerol... 

A rather limited collection of simple precursor molecules is sufficient to provide for the biosynthesis of virtually any cellular constituent, be it protein, nucleic acid, lipid, or polysaccharide. All of these substances are constructed from appropriate building blocks via the pathways of anabolism. In turn, the building blocks (amino acids, nucleotides, sugars, and fatty acids) can be generated from metabolites in the cell. For example, amino acids can be formed by amination of the corresponding a-keto acid carbon skeletons, and pyruvate can be converted to hexoses for polysaccharide biosynthesis. 

Many experimental variations are possible when performing uptake studies [246]. In a simple experiment for which the cells are initially free of internalised compound, the initial rates of transmembrane transport may be determined as a function of the bulk solution concentrations. In such an experiment, hydrophilic compounds, such as sugars, amino acids, nucleotides, organic bases and trace metals including Cd, Cu, Fe, Mn, and Zn [260-262] have been observed to follow a saturable uptake kinetics that is consistent with a transport process mediated by the formation and translocation of a membrane imbedded complex (cf. Pb uptake, Figure 6 Mn uptake, Figure 7a). Saturable kinetics is in contrast to what would be expected for a simple diffusion-mediated process (Section 6.1.1). Note, however, that although such observations are consistent... 

TLC has similar applications to paper chromatography. The stationary phase is a coating, such as silica gel, on a glass or plastic plate. Depending on the TLC plate used, components may be separated based on differences in molecular weight, charge, or polarity (see Chapter 11). TLC with a 70% isopropyl alcohol mobile phase and a silica gel plate is an effective substitute for paper chromatography separation of amino acids. Nucleotides may be separated on a special silica gel plate and a 20% ethanol (in water) mobile phase. 

Tissue culture, more frequently used as cell culture, enables animal and plant cells to be cultured in large numbers by techniques comparable to those used in microbiology but, because of the fragile nature of the cells, does require special cultural conditions. The culture media used must supply all the essential factors for growth, such as a wide range of amino acids, nucleotides, enzyme co-factors as well as indeterminate factors that can only be supplied in special products, e.g. foetal bovine serum. The environmental conditions must be carefully controlled, particularly pH, and this is frequently maintained by culturing in a bicarbonate buffer system and a carbon dioxide saturated atmosphere. 

The power and potential of microorganisms to adapt and prosper in a wide range of environments are well known. They have the ability to break down high molecular weight carbon and energy sources into small molecules, convert these to primary metabolites such as amino acids, nucleotides, vitamins, carbohydrates, and fatty acids, and finally build these basic materials into proteins, coenzymes, nucleic acids, mucopep-tides, polysaccharides and hpids used for growth. 

The versatility of microbial natural products is enormous. The most industrially important primary metabolites are the amino acids, nucleotides, vitamins, solvents, and organic acids. Millions of tons of amino acids are produced each year with a total mulfibillion dollar market. 

Environmental Amino acids, nucleotides. Lower eukaryotes (cell growth,... 

Biosynthesis of Amino Acids, Nucleotides, and Related Molecules 843... 

Biosynthesis of amino acids, nucleotides, and biological amines... 

BIOSYNTHESIS OF AMINO ACIDS, NUCLEOTIDES, AND RELATED MOLECULES... 

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