Arabinose with glutamic acid

The peptide moiety of wax D fractions of human strains seems to be necessary for the activity of these fractions as immunological adjuvants (see p. 235) this may be due to the close chemical similarity between the structure of the water-soluble portion of wax D and the cell wall of Mycobacteria, since the latter contains the same three amino acids (alanine, glutamic acid, and a, c-diaminopimelic acid) and the same sugars (arabinose, mannose, galactose, and aminohexoses). Wax D of human strains might be considered to be a monomer of the cell wall, heavily esterified with mycolic acid. 

Routes have been developed for the synthesis of P-L-didehydrodideoxy-nucleosides in the purine series (60, B=Ade, Gua, Hypoxanthine), and the corresponding hydrogenated compounds, starting from either L-xylose or from D-glutamic acid. The L-nucleoside derivative 61 has been prepared by known methods from L-arabinose, and was converted to p-L-d4C (60, B=Cyt), via 62 as an intermediate. Transglycosylation of 61 with 5-fluorouracil was used to make the L-enantiomer of 5-fluoro-d4C (60, B=5-fluoro-Ura). Some of these L-enantiomers have potent anti-HIV and anti-HBV activity. 

The gradients of H, Na, and other cations and anions established by ATPases and other energy sources can be used for secondary active transport of various substrates. The best-understood systems use Na or gradients to transport amino acids and sugars in certain cells. Many of these systems operate as symports, with the ion and the transported amino acid or sugar moving in the same direction (that is, into the cell). In antiport processes, the ion and the other transported species move in opposite directions. (For example, the anion transporter of erythrocytes is an antiport.) Proton symport proteins are used by E. coU and other bacteria to accumulate lactose, arabinose, ribose, and a variety of amino acids. E. coli also possesses Na -symport systems for melibiose as well as for glutamate and other amino acids. 

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