Amino acids terminal

Application of the Horner-Wadsworth-Emmons reaction to the functionalization of dendrimers allows one to prepare amino acid terminated macromolecules. Such a reaction conducted with dendrimers 10-[G ], 10-[G 3], lO-fG ] and phosphonates unsubstituted at the carbon a to the phosphoryl group affords in moderate yield dendrimers bearing various a, / unsaturated functional groups on the surface [18]. (Schemes 17 and 18). 

Cheng Q, Yamamoto M, Stevens RC. Amino acid terminated polydiacetylene lipid microstmc-tures morphology and chromatic transition. Langmuir 2000 16 5333-5342. 

The 20 amino acid terminal segment specific to the secreted form of the p chain contains the half-cystine residue that forms a disulfide bridge to the J (joining) chain, a polypeptide that is found exclusively in polymeric immunoglobulins (reviewed by Koshland, 1985 not to be confused with the J gene segment with which it has nothing in common, except one letter of the alphabet). 

Figure 7 Schematic presentation of the synthesis of the amino acid-terminated poly(pro-pylene imine) dendrimers, including an atomic numbering of the shell of the dendritic box...

Human insulin (humulin) is prepared by recombinant DNA technology or is synthesized from porcine insulin (enzymatic replacement of the terminal arginine with threonine). Human insulin is preferred to insulin prepared from animals because it is less antigenic. Porcine insulin differs from human insulin by one amino acid (terminal arginine). Bovine insulin is the most immunogenic preparation. A typical dosing... 

The pentapeptide chains of peptidoglycans have a sequence of amino-acids terminated with D-Ala-D-Ala at positions 4 and 5. Possible conformations of D-Ala-D-Ala and its analogues L-Ala-D-Ala, D-Ala-L-Ala, D-butyryl-L-Ala, D-Ala-D-butyric acid, D-Val-D-Ala, and D-Ala-D-Val have been analysed by theoretical methods.From theoretical studies it is predicted that L-Ala or D-Val at the 4 or 5 position of the pentapeptide group of the peptidoglycan will reduce the cross-linking in peptidoglycan biosynthesis, whereas the effect of D-butyric acid will be marked at the 4 position and moderate at the 5 position. This is in agreement with experimental results. 

Amino acid-terminated anq>hiphilic and bolaanq)hiphilic diacetylene lipids were synthesized and assembled to form microstructures of varied morphologies. UV irradiation of the assemblies leads to conjugated polymers with unique optical properties. Chromatic transition of polydiacetylene materials in response to pH and thermal effect and their morphological transformation upon lipid doping are discussed. 

Figure 1. Synthetic scheme and molecular structures of amino acid terminated...

Figure 2 shows the TEM images of microstructures made from amino acid terminated diacetylene lipids. For L-Glu-PDA (Fig. 2A), the aggregate consists of twisted and untwisted ribbons and fibers, with their lengths var5ring from... 

The colorimetric properties of amino acid terminated PDAs were investigated by diermochromism and solution pH induced chromism. Quantitative analysis of chromatic transition was conducted by analyzing the colorimetric response (CR) as a function of solution pH (IS). The CR is defined as the percent change in the maximum adsorption at 646 nm with respect to the total aWrption at 542 nm and 646 nm. Figure 3 shows the CR vs. pH for the amino acid terminated PDA microstructures. Sigmoidal ciuwes were obtained... 

Amino acid-terminated boiaamphiphiiic diacetylene lipid... 

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