Aspartic acid metal complexes

Asparagine prebiotic systems, 871 Aspartate transcarbamylase zinc, 606 Aspartic acid metal complexes, 858 prebiotic systems, 871 Aspartic acid, p-carboxy-synthesis... 

In addition to this we have several examples of which the polymer conformation of the polymeric complex leads the asymmetrical selectivity Hydrogenation reactions of 1-methylcinnamic acid and 1-acetamidocinnamic acid by several poly(L-amino acid)-Pd complexes are observed (142-144). Poly(L-valine) (/3-form) and poly(/3-benzyl-L-aspartate) (a-helix, sinistral) give dextrorotative products, and poly(L-leucine) and poly( 3-benzyl-L-aspartate) (a-helix, dextral) do levo-rotatory products. Also, optical active poly-/3-hydroxyl esters-Raney Ni catalyst (145) and Ion-exchange resin modified by optical active amino acid-metal complex (146,147) are observed in asymmetrically selective hydrogenations. 

In general, transition metal ions are undesired in protein formulations because they can catalyze physical and chemical degradation reactions in proteins. However, specific metal ions are included in formulations when they are cofactors to proteins and in suspension formulations of proteins where they form coordination complexes (e.g., zinc suspension of insulin). Recently, the use of magnesium ions (10-120 mM) has been proposed to inhibit the isomerization of aspartic acid to isoaspartic acid (63). 

In ordinary plants the evidence is for the involvement of anionic complexes of Cu and Ni for uptake and transport. This is generally taken as resulting from citrate rather than amino add complexation [as neutral bis(amino acidato)metal(II) complexes]. However, this conclusion ignores the presence of aspartic add, which is often found in exudates in relatively large amounts and would form bis-anionic spedes. A metal binding role for aspartic acid in xylem sap was proposed in some earlier work.37... 

Nishiyama, N., Yokoyama, M., Aoyagi, T., Okano, T., Sakurai, Y. and Kataoka, K. (1999) Preparation and characterization of self-assembled polymer-metal complex micelle from cis-dichlorodiammineplatinum(II) and poly(ethylene glycol)-poly(, -aspartic acid) block copolymer in an aqueous medium. Langmuir, 15, 377-383. 

Use Biological and clinical studies, preparation of culture media, organic intermediate, ingredient of aspartame, detergents, fungicides, germicides, metal complexation. Available commercially as dl(—)-, l(+)-, and DL-aspartic acid. 

Previous studies have reported silver staining with other amino acids. Heukeshoven and Dernick reported silver staining of the homopolymers of glycine, serine, proline and aspartic acid (4 ) while Nielsen and Brown reported the formation of colored silver complexes with aspartate, and tyrosine (45,). Staining of these homopolymers was not observed in the study of Merril and Pratt (32,), and prior metal binding studies failed to demonstrate metal interactions with the side-chain hydroxyl groups of serine, threonine or tyrosine... 

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