Amino acid surfactants arginine

Amino acid surfactants (AAS), both natural and synthetic types, have been the subject of many smdies, due mostly to their huge potential application in pharmaceutical, cosmetic, household, and food products. The AAS are derived from acidic, basic, or neutral amino acids. Amino acids such as glutamic acid, glycine, alanine, arginine, aspartic acid, leucine, serine, proline, and protein hydrolysates have been used as starting materials to synthesize AAS commercially and experimentally. Methods of preparation include chemical, enzymatic, and chemoenzymic processes, although chemical processes have been prevalent due to their relatively low cost of production. In recent years, more research papers have focused on the use of enzymatic methods to synthesize AAS. It is our opinion that the enzymatic approach would be more attractive to manufacturers in the near future. 

Lipase Amino acid surfactants Ester bond formation between free fatty acids and hydroxyls of arginine esterified to glycerol Infante et al., 2009... 

Similar nanotube types were also prepared form peptide amphiphiles made of a hydrophilic head with one or two charged amino acids and a hydrophobic tail of four or more consecutive hydrophobic ones. Between the studied hydrophobic amino acids, alanine and valine produce more homogeneous and stable nanotubes than glycine, isoleucine, and leucine. On the other hand, lysine or histidine is preferred over arginine, possibly due to steric effects. The tubes are stabilized mainly by the hydrophobic effects similar to the LNTs, albeit the diameter is around an order of magnitude smaller. Unlike conventional surfactants. 

Recently, Infante et al. [51] synthesized acidic and basic A -lauroyl arginine dipeptides, as methyl esters and free carboxylic acids, from pure amino acids. They found that amphoteric A -lauroyl-l-arginine dipeptide surfactants containing glutamic acid or lysine had no antimicrobial activities. However, the cationic versions of these peptides were antimicrobial, particularly the dipeptide derivatives containing lysine [51]. 

Amino acids have two functional groups, the carboxylic group and the amino group, which can be converted to surfactant with a reactive molecule bearing a hydrophobic chain. Amino acids with reactive sidechains, such as lysine, arginine, aspartic acid, and glutamic acid, offer opportunities for the molecular design of AAS. 

A -Acylamino acids with basic amino acids such as lysine and arginine have an amphoteric structure. However, the solubility of the salt of these molecules is too poor to utilize them as a practical surfactant. Several modifications are applied to improve their solubility. Sakamoto et al. [45] reacted Al -acyllysine with ethylene oxide to introduce the polyoxyethylene group, whereas Sagawa et al. introduced additional the Af-methyl group. Both methods led to lysine derivatives with surface activities that were pH dependent (Fig. 18 and 19) because of their amphoteric structures [54-57]. 

Water-soluble antimicrobial Upopeptides have been prepared by the condensation of amino acids or peptides to lV -acyl arginine residues with suitable lipophilic contents. Our data suggest that such arginine lipopeptidic surfactants have value as soft preservatives in cosmetic, food, and dermopharmaceutical formulations, as well as being tools for fundamental research. 

Vinardell and co-workers [135] studied the irritation of rabbit eye and skin from cationic amino acid-derived surfactants iV-acyl-L-arginine methylesters. They found that amino acid-based surfactants are less irritant than a conventional cationic surfactant, cetrimide. Also, the degree of irritation depends on the chain length of the alkyl group, and a maximum of irritation was observed for Ci2 surfactant. The similar effect was reported for alkyl sulfates before [136], being ascribed to the high monomer concentration of surfactant. 

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." ... 

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