Attribute synthesis specific

Another reason for concluding that peptide antibiotics are not synthesized by the kind of template mechanism that is operative in protein formation is that variation of amino acids in the environment can shift the proportion of the molecular species of peptides that are being produced. In protein synthesis, specificity of amino acid sequence is under direct genetic control and single amino acid substitutions in such proteins as hemoglobin, tryptophane synthetase, or phage coat proteins are attributed to alteration in the nucleotide sequence of structural genes rather than to environmental variation (Mach and Tatum, 1964). 

Substructure searches provide another method of searching for available starting materials. They arc used primarily for planning the synthesis of combinatorial libraries. After the target compound has been dissected into a set of suitable precursors, substructure searches can provide for each of them a series of representatives of a certain class of compounds, Siibsti ucturc searches enable the user to specify attributes such as open sites or atom lists at certain positions of the structure. Figure 10.3-38 shows the possible specification elements for the query in a substructure search. 

Formation of the oxazoline reduced undesirable 18F-19F exchange and the desired product was rapidly (15s) isolated in good yield (45-55%) with a specific activity (1.1 GBq pmol-1) that was 20 times higher than that obtained when using direct debromination route. In another example, the synthesis of 2-deoxy-2-18F-fluoro-D-glucose [110] the high purity of the product and the improved specific activity is attributed to the short reaction times that are made possible via the use of micro-... 

The exact mechanism of the immunogenicity of species-specific rDNA proteins is unknown, but is believed to be attributable to (1) the addition of extra amino acid residues during synthesis, which the host reads as foreign (2) denaturing of the native molecules or (3) contamination by E. coli polypeptides or lipopolysacchar-ides. 

Enzymatic polymerizations have been established as a promising and versatile technique in the synthetic toolbox of polymer chemists. The applicability of this technique for homo- and copolymerizations has been known for some time. With the increasing number of reports on the synthesis of more complex structures like block copolymers, graft copolymers, chiral (co)polymers, and chiral crosslinked nanoparticles, its potential further increases. Although not a controlled polymerization technique itself, clever reaction design and integration with other polymerization techniques like controlled radical polymerization allows the procurement of well-defined polymer structures. Specific unique attributes of the enzyme can be applied... 

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