Surfactants peptide based

Although this book is focused primarily on the synthesis and application of PBS from renewable sources or waste products, some naturally occurring PBS will also be discussed briefly. Some of these naturally occurring PBS have found applications in the pharmaceutical and personal care industries. Also, this book is primarily about amino acid- and peptide-based surfactants, two types of PBS that are discussed in some detail in the following sections. 

Fluorinated Amino Acid- or Peptide-Based Surfactants... 

FIGURE 29.25 Synthesis of peptide-based gemini surfactant. (Reproduced from McGregor, C., Perrin, C., Monck, M Camilleri, P., Kirby, A.J., J. Am. Chem. Soc., 123, 6215-6220, 2001. With permission.)... 

In order to produce the amphoteric protein-based surfactant, the incorporation of lipophilic amino acid ester was attempted using the one-step method of plastein reaction with papain at pH 9. In a system containing succinylated ttsi-casein as a protein substrate and luecine n-dodecyl ester as a lipophile, the peptide bond between Phe and Tyr of casein was first hydrolyzed, and this is followed by the incorporation of luecine n-dodecyl ester at the same position, forming a new C-terminus [34]. The structure of the macropeptide with respect to the distribution of hydrophilic amino acid residues is shown in Fig. 4 [29,34]. Amphiphilic structure consisting of hydrophilic protein portion and lipophilic luecine n-dodecyl ester was clearly demonstrated. 

Protein-based surfactants are usually synthesized with amino acids/peptides and fatty acids as building blocks. They are mainly of two types peptide and amino acid surfactants. Both are interesting compounds that contain an amino or a peptide as the hydrophilic part and a long hydrocarbon chain as the hydrophobic portion. The hydrocarbon chain can be introduced through acyl, ester, amide, alkyl, or ether linkage. Protein-based surfactants are usually con-... 

Effects of curcumin, an antioxidant lipophilic drug on membrane structure by Solid-State NMR Spectroscopy. xviii. The elfect of the cationic, helical peptide based on the essential lung surfactant protein B on oriented lipid bilayers characterized by H... 

Graf, A., Ablinger, E., Peters, S., Zimmer, A., Hook, S. M., and Rades, T. 2008. Microemukions containing lecithin and sugar-based surfactants Nanoparticle templates for delivery of proteins and peptides. International Journal of Pharmaceutics, 350(1-2), 351-360, 2008. 

One important milestone in our research is the design and development of new amino acid-based surfactants with antimicrobial properties, which mimic natural amphiphilic cationic peptides [42,43]. To this end, Lys and Arg derivatives of long-chain A -acyl, COO-ester, and A-alkyl amide have been prepared. In particular, the A -acylarginine methyl ester derivatives series 1 (Scheme 1) have turned out to be an important class of cationic surface active compounds with a wide bactericidal activity, high biodegradability, and low toxicity profile. We have shown that essential structural factors for their antimicrobial activity include both the length of the fatty residue (akin with their solubility and surface activity) and the presence of the protonated guanidine function [43,44]. 

Lowik, D.W.PM. and Van Hest, J.C.M. (2004) Peptide based amphiphiles. Chemical Society Reviews, 33,234—245. Lui, S. andArmes, S.P (2001a) Recent advances in the synthesis of polymeric surfactants. Current Opinion in Colloid Interface Science, 6,249-256. 

Rl, R2, and R5 peptides, three amino acid sequences found in the sillp protein (Fig. 3), were used in vitro to study the silica formation. It was revealed that these polypeptides also form silica upon the addition of TMOS solution. Another investigation made use of arginine-based surfactants to synthesize mesoporous silica." ... 

Recently, peptoid-based mimics of both SP-C and SP-B have been designed to adopt helical secondary structures, and also mimic (to varying degrees) the sequence patterning of hydrophobic and polar residues found in the natural surfactant proteins. Peptoid-based SP-C mimics of up to 22 monomers in length, were synthesized and characterized by in vitro experimental methods [67, 68] (Fig. 1.8). The secondary structure of all molecules was assessed by circular dichroism and found to be helical. The surface activities of these peptoids, in comparison to the actual SP peptides described above, were characterized by surfactometry using... 

Depicted in Fig. 2, microemulsion-based liquid liquid extraction (LLE) of biomolecules consists of the contacting of a biomolecule-containing aqueous solution with a surfactant-containing lipophilic phase. Upon contact, some of the water and biomolecules will transfer to the organic phase, depending on the phase equilibrium position, resulting in a biphasic Winsor II system (w/o-ME phase in equilibrium with an excess aqueous phase). Besides serving as a means to solubilize biomolecules in w/o-MEs, LLE has been frequently used to isolate and separate amino acids, peptides and proteins [4, and references therein]. In addition, LLE has recently been employed to isolate vitamins, antibiotics, and nucleotides [6,19,40,77-79]. Industrially relevant applications of LLE are listed in Table 2 [14,15,20,80-90]. 

Protein is an excellent natural nanomaterial for molecular machines. Protein-based molecular machines, often driven by an energy source such as ATP, are abundant in biology. Surfactant peptide molecules undergo self-assembly in solution to form a variety of supermolecular structures at the nanoscale such as micelles, vesicles, unilamellar membranes, and tubules (Maslov and Sneppen, 2002). These assemblies can be engineered to perform a broad spectrum of functions, including delivery systems for therapeutics and templates for nanoscale wires in the case of tubules, and to create and manipulate different structures from the same peptide for many different nanomaterials and nanoengineering applications. 

Shea and colleagues [109-111] added an exciting contribution to this field They created molecular imprints for the peptide melittin, the main component of bee venom, in polymer nanoparticles, resulting in artificial antibody mimics that can be used for the in vivo capture and neutralization of melittin. Melittin is a peptide comprising 26 amino acids which is toxic because of its cytolytic activity. Shea and colleagues strategy was to synthesize cross-linked, acrylamide-based MIP nanoparticles by a process based on precipitation polymerization using a small amount of surfactant. To maximize the specificity and the affinity for melittin, a number of hydrophilic monomers were screened for complementarity with the template. The imprinted nanoparticles were able to bind selectively the peptide with an apparent dissociation constant of Ax>app > 1 nM [109]. 

Many pharmaceutical preparations contain multiple components with a wide array of physico-chemical properties. Although CZE is a very effective means of separation for ionic species, an additional selectivity factor is required to discriminate neutral analytes in CE. Terabe first introduced the concept of micellar electrokinetic capillary chromatography (MEKC) in which ionic surfactants were included in the running buffer at a concentration above the critical micelle concentration (CMC) [17], Micelles, which have hydrophobic interiors and anionic exteriors, serve as a pseudostation-ary phase, which is pumped electrophoretically. Separations are based on the differential association of analytes with the micelle. Interactions between the analyte and micelles may be due to any one or a combination of the following electrostatic interactions, hydrogen bonding, and/or hydro-phobic interactions. The applicability of MEKC is limited in some cases to small molecules and peptides due to the physical size of macromolecules... 

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