D-Asparagine

Different optical enantiomers of amino acids also have different properties. L-asparagine, for example, tastes bitter while D-asparagine tastes sweet (see Figure 8.3). L-Phenylalanine is a constituent of the artificial sweetener aspartame (Figure 8.3). When one uses D-phenylalanine the same compound tastes bitter. These examples clearly demonstrate the importance of the use of homochiral compounds. 

H. Roy, Evolution des voies de formation d asparagine et d asparaginylation de I ARNt. Ph.D. Thesis, Universite Louis Pasteur, Strasbourg, France, 2002. 

A. PiUTTi. Sur une nouvelle espice d asparagine. Compt. rend., 1886, 103, 134-137. 

D-Asparagine (D-a -amino acid) From I-Asparagine racemization Sweet... 

D-Alanine [161] Bacillus subtilis D-Glutamate D-Aminobutyrate D-Aspartate D-Asparagine D-Norvahne a-Oxoglutarate... 

Figure 2.31. (a) Dependence of peak height on coil length L measured for the reaction between o-phthalaldehyde and four aminoacids a, glycine b, serine c, phenylalanine d, asparagine (b) Reaction rate curves computed from measured D values and from data of (a) by means of Eq. (2.44). The increasing slope of the curves from d to a shows the increase of reaction rate. %E refers to the degree of conversion reached.)... 

Piutti A. Su rune nouvelle espec d asparagine. Compt Red 1886 103 134-138. 

Asparaginase Magnetic polyacrylamide gel with immobilized D-asparagine [119]... 

Explain why natural L-asparagine is bitter, whereas artificial D-asparagine is sweet. Exercise 3.11... 

Echavarren, A. Galan, A. Mendoza, J. Salmeron. A. Lehn, J.-M. Anion receptor molecules Synthesis of a chiral and functionalized binding subunit, a bicyclic guanidinium group derived from L- or D-asparagine. Helv. Chim. Acta 1988. 71 (4). 685-693. 

Although only L-amino acids occur in proteins, D-ami-no acids are often a part of the metabolism of lower organisms.The antibiotic actinomycin D, for example, contains a unit of D-valine, and the antibiotic bacitracin A contains units of D-asparagine and D-glutamic acid. Draw Fischer projections and three-dimensional representations for these three D-amino acids. 

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