Hydrophilic peptides

Key words DRV, Protein, Peptide, Hydrophilic drug. Encapsulation yield. Vaccine, DNA, Particulate, Bacteria, Cyclodextrin... 

Figure 7.35 GroEL peptide substrates (a) Basic Amphiphilic (Bamph) peptide, the optimal first round substrate peptide. Hydrophilic residues (red) and hydrophobic residues (green) are disposed for B h to have the ability to form an amphiphilic a-helix in solution (left), considered to be potentially optfmal to interact with exposed hydrophobic residue "patches" in GroEL (coloured regions in GroEL monomer riahti (b) Summary of AMPH and NON-AMPH series peptides with helix forming template (Ro 47-1615) and control template (Ro 47-1614) (right) and proposed amphiphilic (AMPH) (upper left) and non-amphiphilic (NON-AMPH) helical structures (lower left) illustrated (peptide structure illustrations in a) and b) are adapted from Preuss et al., 1999, Fig. 3).

Hydrophilic polymers generally do not self-assemble in aqueous solution hence, the assembly of peptide-hydrophilic polymer conjugates reUes on the peptide... 

Other studies [85] have shown that cationic bacitracin, anionic AOT, and nonionic Tween 80 all enhanced cellulose hydrolysis, implying that the charge of the surfactant was not an important consideration. In fact. Tween 80 (0.1%) increased the rate and extent of saccharification by up to 40% [82,85]. The structure of the hydrophilic head group of the surfactant also had little significance [85], Those with a sugar group, sophorolipid and rhamnolipid, worked well, as did bacitracin, which has a peptide hydrophilic group [85]. 

Gorecki and Patchornik (1973) made a polymer in which dihydrolipoic acid was covalently bound to the polymer via its carboxyl group. Since the reagent polymer was ultimately designed to be used for the reduction of proteins and peptides, hydrophilic support polymers (e.g., aminoethyl Sephadex G-25, aminoethyl polyacrylamide and aminoethyl cellulose) were preferred. In a more recent application, the compound was linked to controlled-pore glass (Scouten and Firestone, 1976). 

Potential ionic interactions may also be provided by the free amine groups of the arginine fragment. As a consequence, the net character of the heptapeptide will be polar, and the peptide would be classed as hydrophilic or lyophilic in nature. 

Amphoteric hydrophilic Peptides, proteins, poly and oligosaccharides, DNA, RNA Buffer or salt solution (e.g., 0.1 M NaNO,)... 

The neutral hydrophilic surface and the wide range of pore diameters available for SynChropak GPC allow many compounds from small peptides to nucleic acids and other polymers to be analyzed. Table 10.2 lists the approximate exclusion limits for both linear and globular solutes. Although this information... 

Superose gel material of Pharmacia Biotech is a highly epichloro-hydrine cross-linked agarose matrix that has a pH range of 3-12 (short term 1-14). Hydrophilic interactions may be noticeable for lipids, peptides, and small aromatic compounds, but such interactions might even improve resolution. Superose medium is available in two different porosities Superose 6 HR 10/ 30 (bead size 13 2 /um maximum pressure 1.5 MPa) and Superose 12 HR 10/30 (bead size 10 2 /um maximum pressure 3.0 MPa). 

This ester was developed to impart greater hydrophilicity in C-terminal peptides that contain large hydrophobic amino acids, since the velocity of deprotection with enzymes often was reduced to nearly useless levels. Efficient cleavage is achieved with the lipase from R. niveus (pH 7, 37°, 16 h, H2O, acetone, 78-91% yield)... 

Some authors have suggested the use of fluorene polymers for this kind of chromatography. Fluorinated polymers have attracted attention due to their unique adsorption properties. Polytetrafluoroethylene (PTFE) is antiadhesive, thus adsorption of hydrophobic as well as hydrophilic molecules is low. Such adsorbents possess extremely low adsorption activity and nonspecific sorption towards many compounds [109 111]. Fluorene polymers as sorbents were first suggested by Hjerten [112] in 1978 and were tested by desalting and concentration of tRN A [113]. Recently Williams et al. [114] presented a new fluorocarbon sorbent (Poly F Column, Du Pont, USA) for reversed-phase HPLC of peptides and proteins. The sorbent has 20 pm in diameter particles (pore size 30 nm, specific surface area 5 m2/g) and withstands pressure of eluent up to 135 bar. There is no limitation of pH range, however, low specific area and capacity (1.1 mg tRNA/g) and relatively low limits of working pressure do not allow the use of this sorbent for preparative chromatography. 

Recently, unique vesicle-forming (spherical bUayers that offer a hydrophilic reservoir, suitable for incorporation of water-soluble molecules, as well as hydrophobic wall that protects the loaded molecules from the external solution) setf-assembUng peptide-based amphiphilic block copolymers that mimic biological membranes have attracted great interest as polymersomes or functional polymersomes due to their new and promising applications in dmg delivery and artificial cells [ 122]. However, in all the cases the block copolymers formed are chemically dispersed and are often contaminated with homopolymer. 

Beausoleil, E., Truong, K.T., Kirshenbaum, K., and Zuckermann, R.N. Influence of monomer structural elements in hydrophilic peptoids. In Innovations and Perspectives in Solid Phase Synthesis and Combinatorial Libraries Peptides, Proteins, and Nucleic Acids, R. Epton (Ed.), 2001, Mayflower Scientific Press Kingswin-ford, UK, pp. 239-242. 

Tropoelastin is the soluble precursor of elastin and consists of alternating hydrophobic and hydrophilic peptide domains. The most common amino acids in the hydrophobic domains are Gly, Val, Ala, and Pro, which are often present in repeats of tetra-, penta-, and hexapeptides, such as Gly-Gly-Val-Pro, Gly-Val-Gly-Val-Pro, Gly-Val-Pro-Gly-Val, and Gly-Val-Gly-Val-Ala-Pro, respectively [3, 4]. The hydrophilic domains are mainly composed of lysines interspersed by alanines. 

Fig. 1 Primary structure of human tropoelastin isoform 3 (EBI accession no. P15502). The highlighted regions correspond to the signal peptide and hydrophobic and hydrophilic domains. Based on [2]...

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