Lysine cation

Formation of a complex between DNA and polycationic compounds appears to be the initial and quite possibly a critical parameter for nonviral gene delivery. Several synthetic vector systems, which are generally cationic in nature, including poly(lysines), cationic liposomes or various types of block copolymers and recently dendrimers, have been shown to self-assemble with plasmid DNA [13-15] [16]. Specific physicochemical properties manifested by these DNA complexes depend on the type of cationic agent used however, interesting patterns for such interactions are beginning to evolve [17, 18]. Under certain conditions, the interaction of DNA with polyvalent cations results in... 

In conclusion it was shown that the solid-state complexes formed by poly(L-arginine), poly(L-histidine) and poly(L-lysine) cations and retinoic acid can be prepared as films and nano-particles. The high content of retino-ate moieties, the absence of crystallinity and low particle sizes could make these complexes interesting as a new carrier for the delivery of retinoic acid, either transdermal or in body fluids. It may be speculated that supramolecu-lar structures such as the smectic A-like nano-particles of the tart-type pre-... 

In one sense, this has been the approach in any broad, synthetic approach where a systematic replacement of substituents is done on a reference molecule. Assumptions are made that aliphatic moieties fit into hydrophobic pockets, anionic residues bind by an ionic bond to a positive charged group such as the c-amino of lysine, cationic residues bind by a salt linkage to the anionic residues of aspartic or glutamic acids, alcohols and amides hydrogen bond to electron rich moieties such as oxygen, nitrogen and sulfur functions. 

Stoichiometric complexes of poly(L-lysine) cations and dodecyl sulfate anions were investigated by Ponomarenko et al. [51,52]. The complexes are prepared by the same method used in the preparation of poly(y,L-glutamic acid)-alkyltrimethylammonium complexes. The secondary stmcture adopted by the polypeptide in these complexes was found to be very susceptible to environmental conditions. In chloroform solution containing 1 to 2% (v/v) TFA the polypeptide chain is in the a-helical con formation whereas a disordered state is present at TFA concentrations above 5%. It was interesting to observe that a noticeable decrease in the spin-lattice relaxation time accompanied the helix-coil... 

Stoichiometric complexes of poly(L-lysine) cations and dodecyl sulfate anions were investigated by Ponomarenko et al. [48,49]. The complexes are prepared by the same method used in the preparation of poly(Y,L-glutamic acid)-alkyltri-... 

Although the order of affinity of PF-4 for different glycosaminogly-cans, and dissociation of their complexes with salts, are typical of nonspecific, electrostatic interactions, PF-4 is not strictly a cationic protein.452 It is probable that heparin binds to clusters of basic amino acids (two lysine pairs) near the carboxyl terminal of a polypeptide chain that has an overall preponderance of acidic amino acid residues.457 High-molecular-weight heparin species can bind two PF-4 molecules, with formation of complexes 10 to 100 times as strong as those with antithrombin.217... 

POLY(AMINO acids). Both anionic [e.g., poly(L-aspartic acid) and poly(glutamic acid)] and cationic [e.g., poly[L-lysine)] poly(amino acids) have been suggested as potential drug carriers. Poly(L-lysine) is a homopolymer cosisting of repeating units of L-lysine. It exhibits some affinity for cancer cells and possesses antimicrobial and antiviral properties. It also shows... 

The most common carrier proteins in use today are keyhole limpet hemocyanin (KLH MW 4.5 X 105 to 1.3 X 107), BSA (MW 67,000), aminoethylated (or cationized) BSA (cBSA), thyroglobulin (MW 660,000), ovalbumin (OVA MW 43,000), and various toxoid proteins, including tetanus toxoid and diphtheria toxoid. Other proteins occasionally used include myoglobin, rabbit serum albumin, immunoglobulin molecules (particularly IgG) from bovine or mouse sera, tuberculin purified protein derivative, and synthetic polypeptides such as poly-L-lysine and poly-L-glutamic acid. 

In this paper we briefly describe the apparatus and experimental method, then consider the interactions between i) layers of polystyrene in cyclohexane under poor-solvent and ii) 0 - solvent conditions,iii) the interactions between adsorbed PEO layers in a good (aqueous) solvent and iv) the surface forces between layers of adsorbed poly-L-lysine, a cationic polyelectrolyte, in aqueous salt solutions. We consider briefly the implications of our results for the current theoretical understanding. 

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