Polyaspartic acids

In 2000, the first example of ELP diblock copolymers for reversible stimulus-responsive self-assembly of nanoparticles was reported and their potential use in controlled delivery and release was suggested [87]. Later, these type of diblock copolypeptides were also covalently crossUnked through disulfide bond formation after self-assembly into micellar nanoparticles. In addition, the encapsulation of l-anilinonaphthalene-8-sulfonic acid, a hydrophobic fluorescent dye that fluoresces in hydrophobic enviromnent, was used to investigate the capacity of the micelle for hydrophobic drugs [88]. Fujita et al. replaced the hydrophilic ELP block by a polyaspartic acid chain (D ). They created a set of block copolymers with varying... 

In another study, polyaspartic acid was examined as a corrosion inhibitor for steel as a function of pH and temperature [1629]. At low to neutral pH values, polyaspartic acid increases the corrosion rate of steel. At pH values above 10, polyaspartic acid is a reasonably robust corrosion inhibitor. 

D. C. Silverman, D. J. Kalota, and F. S. Stover. Effect of pH on corrosion inhibition of steel by polyaspartic acid. In Proceedings Volume. 50th Annu NACE Int Corrosion Conf (Corrosion 95) (Orlando, FL, 3/26-3/31), 1995. 

Compare the alkalimetric titration of a polyprotic acid (e.g., polyaspartic acid) with that of an Al203 dispersion show in either case the effect of the presence of a metal ion (e.g., Cu2+) on the titration curve. 

The pharmacokinetics of a radiopharmaceutical can be systematically altered by chemical modification of the targeting biomolecule or metal chelate, and the use of a pharmacokinetic modifying Hnker. The chemical modification of a biomolecule can be achieved by introducing various hydrophiUc or Hpophilic groups onto the side-chains of the targeting biomolecule. Sometimes a peptide sequence, such as polyaspartic acid, can be used to improve the hydrophiUcity. The chemical modification of the metal chelate can be achieved using BFCs with different charge and hydrophiUcity. 

Carbonic anhydrase, myoglobin, amylase, trypsinogen, ribonuclease A, chymotrypsi-nogen A, mesityl oxide Polyaspartic acid immobilized on the capillary wall Salt or pH gradient elution in phosphate buffer (pH 6.0) or isocratic elution with 100 mM NaCl in 10 mM phosphate (pH 6-8) 400 mm x 75 pm i.d. 250 mm active length... 

Wang, X., and Lee, B.I., Dispersion of barium titanate with polyaspartic acid in aqueous media. Colloids Surf., 202, 71, 2002. 

KIshore BK, Lambricht P, Laurent G, Maldague P, Wagner R,Tulkens PM, Mechanism of protection afforded by polyaspartic acid against gentamicin-Induced phosphollpidosis. II. Comparative In-vltroand In-vivo studies with poly-L-aspartIc, poly-L-glutamIc and poly-D-glutamIc acids, J Pharmacol ExpTherap, 1990,255(2) 875-85. 

Ramsammy LS, Josepovltz C, Lane BP, Kaloyanides, Polyaspartic acid protects against gentamicin nephrotoxicity In the rat, J Pharmacol ExpTherap, 1989, 250(1) 149-53. 

Gilbert DN, Wood CA, Kohihepp SJ, Kohnen PW, Houghton DC, Finkbeiner HC, Lindsley J, Bennett WM, Polyaspartic acid prevents experimental aminoglycoside nephrotoxicity, J Infect Dis, 1989,159(5) 945-53. 

Swan SK, Gilbert DN, Kohihepp SJ, Leggett JE, Kohnen PW, Bennett WM, Duration of the protective effect of polyaspartic acid on experimental gentamicin nephrotoxicity, Antimicrob AgentsChemother, 1992, 36(11) 2556-58. 

Tiller and O Melia (1993) compared their polymer adsorption statistics calculations with data from laboratory experiments on the interaction of polyacrylic and polyaspartic acid as well as of humic acids with hematite. Their conclusion is that, at low ionic strength, anionic polyelectrolytes affect the coagulation of positively charged particles by altering the net surface charge in a way similar to that of multivalent, monomeric anions. Steric repulsion, at low ionic strength (i.e., in fresh water), plays little or no role in the stabilization of hematite colloids by the organic macromolecules used in their work calcium... 

COOH Polyacrylic acid Polyaspartic acid Polyglutamic acid Carboxymethylcellulose... 

At pH 7.4 polyaspartic acid would have a large net negative charge on its side chains while polylysine would have a large net positive charge. This would cause repulsion of the R groups and lead to helix destabilization. 

One relatively recent example is the cyanobacterial nitrogen reserve cyanophy-cin (multi-L-arginyl-poly-L-aspartic acid). This polymer is of interest because the oligo-arginyl polyaspartic acid may function as a biodegradable polyelectrolyte in selected applications. This polymer is synthesized in vivo by the enzyme... 

Joentgen, W., Groth, T., Steinbuchel, A., Hai, T., and Oppermann, F.B. (1998) Polyaspartic acid homopolymers and copolymers, biotechnical production and use thereof. Patent application WO 98/39090. 

Polyaspartic acids, in Biopolymers Polyamides and Complex Proteinaceous Materials I, vol. 7 (eds S.R. Fahnenstock and A. Steinbuchel), Wiley-VCH Verlag GmbH, Weinheim, Germany, pp. 175-199. 

Details of experimental procedures are given elsewhere by Liang (14). Deionized distilled water was used to prepare all solutions. All reagents were analytical grade and were used without further treatment. Fatty acids and polyaspartic acids were obtained from Sigma and were at least 99% pure. Fulvic and humic acids were supplied by the International Humic Substances Society. 

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