L- asparagine

M.p. 234-235 C. Hydrolyses to aspartic acid. L-asparagine can be prepared from lupin seedlings, and DL-asparagine is synthesised from ammonia and maleic anhydride. L-asparagine is very widely distributed in plants, being found in all the Leguminosae and Gramineae, and in many other seeds, roots and buds. 

Therapy with L-asparaginase is most successful against tumors exhibiting a deficiency in the synthesis of L-asparagine. Most normal cells exhibit a healthy capacity to synthesize this nonessential amino acid and are not damaged by exposure to L-asparaginase (23). This finding demonstrates that biochemical differences between normal and cancer cells can be exploited for successful cancer chemotherapy. 

L-asparaginase, which catalyzes the hydrolysis of L-asparagine to L-aspartate. 

Chemical Name L-Asparagine amidohydrolase Common Name Colapase L-Asnase Structural Formula ... 

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. 

Carbobenzoxy-L-asparagine (obtained from the Aldrich Chemical... 

A/ -(2-Acetamido-2-deoxy-p-D-glucopyranosyl)-L-asparagine [(GlcNAc-)Asn] or 2-acetamido-A/ -L-P-aspartyl-2-deoxy-p-D-glucopyranosylamine (trivial name p-W-acetylglucosaminyl-L-asparagine)... 

C,7H22N205 94622-86-3) see Deferoxamine A7 -benzyloxycarbonyl-L-asparagine (C12H14N2O5 2304-96-3) see Angiotensinamide Saquinavir... 

Fia. 14.—Superpositioning of d- and L-Asparagine over the Same Receptor Site. 

L-Asparaginase, an enzyme derived from E. coli or Erwinia carotovora, has been employed in cancer chemotherapy where its selectivity depends upon the essential requirement of some tumours for the amino acid L-asparagine. Normal tissues do not require this amino acid and thus the enzyme is administered with the intention of depleting tumour cells of asparagine by converting it to aspartic acid and ammonia. Whilst L-asparaginase showed promise in a variety of experimentally induced tumours, it is only useful in humans for the treatment of acute lymphoblastic leukaemia, although it is sometimes used for myeloid leukaemia. 

Antitumor enzyme, hydrolyzes L-asparagine in bloodstream, depriving tumor cells of the essential amino acid results in inhibition of protein, DNA, and RNA synthesis and cell proliferation derived from Escharichia coli... 

---