Aspartate solubility

It is evident that the area of water-soluble polymer covets a multitude of appHcations and encompasses a broad spectmm of compositions. Proteins (qv) and other biological materials ate coveted elsewhere in the Eniyclopedia. One of the products of this type, poly(aspartic acid), may be developed into interesting biodegradable commercial appHcations (70,71). 

Alitame (trade name Adame) is a water-soluble, crystalline powder of high sweetness potency (2000X, 10% sucrose solution sweetness equivalence). The sweet taste is clean, and the time—intensity profile is similar to that of aspartame. Because it is a stericaHy hindered amide rather than an ester, ahtame is expected to be more stable than aspartame. At pH 2 to 4, the half-life of aUtame in solution is reported to be twice that of aspartame. The main decomposition pathways (Fig. 6) include conversion to the unsweet P-aspartic isomer (17) and hydrolysis to aspartic acid and alanine amide (96). No cyclization to diketopiperazine or hydrolysis of the alanine amide bond has been reported. AUtame-sweetened beverages, particularly colas, that have a pH below 4.0 can develop an off-flavor which can be avoided or minimized by the addition of edetic acid (EDTA) [60-00-4] (97). 

Histidine phosphatases and aspartate phosphatases are well established in lower organisms, mainly in bacteria and in context with two-component-systems . Reversible phosphorylation of histidine residues in vertebrates is in its infancy. The first protein histidine phosphatase (PHP) from mammalian origin was identified just recently. The soluble 14 kD protein does not resemble any of the other phosphatases. ATP-citrate lyase and the (3-subunit of heterotrimeric GTP-binding proteins are substrates of PHP thus touching both, metabolic pathways and signal transduction [4]. 

Figure 9 A synthetic mixture of water-soluble carboxylic acids separated by anion-exchange chromatography. Column 0.3 cm x 300 cm Diaoion CA 08, 16-20 p (Mitsubishi Kasei Kogyo). Eluant 200 mM HC1. Detection reaction with Fe3-benzohy-droxamic acid-dicyclohexy carbodiimide-hydroxylamine perchlorate-triethyl amine with absorbance at 536 nm. Analytes (1) aspartate, (2) gluconate, (3) glucuronate, (4) pyroglutamate, (5) lactate, (6) acetate, (7) tartrate, (8) malate, (9) citrate, (10) succinate, (11) isocitrate, (12) w-butyrate, (13) a-ketoglutarate. (Reprinted with permission from Kasai, Y., Tanimura, T., and Tamura, Z., Anal. Chem., 49, 655, 1977. 1977 Analytical Chemistry).

Synthetic Polymers. Synthetic polymers are versatile and offer promise for both targeting and extracellular-intracellular drug delivery. Of the many soluble synthetic polymers known, the poly(amino acids) [poly(L-lysine), poly(L-aspartic acid), and poly(glutamic acid)], poly(hydroxypropylmethacrylamide) copolymers (polyHPMA), and maleic anhydride copolymers have been investigated extensively, particularly in the treatment of cancers. A brief discussion of these materials is presented. 

Mansour, M., Thaller, S., andKorte, F. Action of sunlight on parathion. Bull. Environ. Contam. Toxicol, 30(3) 358-364,1983. Manzurola, E. and Apelblat, A. Solubilities of L-glutamic acid, 3-nitrobenzoic acid, p-toluic acid, calcium-L-lactate, calcium gluconate, magnesium-DL-aspartate, and magnesium-L-lactate in water, J. Chem. Thermodyn., 34 (7) 1127-1136, 2002. Maraqa, M.A., Zhao, X., Wallace, R.B., and Voice, T.C. Retardation coefficients of nonionic organic compounds determined by batch and column techniques. Soil Sci. Soc. Am. J., 62(1) 142-152, 1998. 

Q78 Compared with soluble insulin, insulin aspart ... 

When compared with soluble insulin, the human analogue insulin aspart has a faster onset and a shorter duration of action, resulting in a higher fasting and preprandial blood glucose concentration. The incidence of hypoglycaemia tends to be lower with insulin aspart than with soluble insulin. 

Glutamic Acid.—The greater part of the glutamic acid is isolated as hydrochloride before the mixture of amino acids is esterified. It is contained with aspartic acid ester in the aqueous solution after the phenylalanine ester has been extracted by ether, and it is separated from aspartic acid, after hydrolysis by baryta, by conversion into its hydrochloride from this it is obtained by treatment with the calculated quantity of soda to combine with the hydrochloric acid and by crystallisation from water, in which it is soluble with some difficulty. 

The mother liquor contains too little DL-aspartic acid to justify its recovery. When the filtrate and washings are evaporated to a syrup and treated with 500 ml. of 95% ethanol, the pyridine hydrochloride dissolves completely, leaving 8-9 g. of crude glycine which yields little or no sparingly soluble DL-aspartic acid on treatment with a minimum quantity of cold water. 

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